chore: gitignore go.work for /tmp worktree resolution

go.work resolves the fn-registry replace to an absolute path when the worktree
lives outside the parent tree; it is local-only and must not be committed.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

.gitignore

@@ -14,3 +14,7 @@ worker.id
 /chat
 *.exe
 registry.db
+
+# local worktree resolution (do not commit)
+go.work
+go.work.sum

app.md

@@ -2,7 +2,7 @@
 name: unibus
 lang: go
 domain: infra
-version: 0.9.0
+version: 0.12.0
 description: "Bus de mensajería unificado sobre NATS+JetStream con cifrado E2E por room (megolm/olm reducido): service de membresía/claves, librería cliente y peers demo."
 tags: [service, messaging, nats, e2e]
 uses_functions:
@@ -122,6 +122,41 @@ Para apuntar a un NATS externo en producción: `--nats-url nats://host:4222` en
   las rutas GET de lectura. Confía en la red interna. Las rutas mutantes
   (`/rooms`, `/invite`, `/rekey`) sí exigen firma Ed25519 del owner sobre los
   bytes canónicos de la request. Endurecer es fase posterior.
+- **Gestión de usuarios: storage unificado, alta por dos vías.** El allowlist de
+  usuarios vive en el MISMO store que las rooms (`pkg/membership.Store`): SQLite en
+  single-node, JetStream KV replicado (`UNIBUS_users`) en cluster. El `Server` ya
+  tiene ese store privilegiado abierto (es quien sirve el KV en cada nodo), así que
+  expone `GET/POST /users` y `POST /users/{signpub}/revoke` como API HTTP admin-only,
+  simétrica con las rutas de rooms: el panel de administración firma como admin y el
+  server ejecuta la mutación contra el mismo store. El panel NO necesita `--db`, ni la
+  identidad interna, ni correr en un nodo del cluster; funciona idéntico en single-node
+  y cluster. La autorización es default-deny: solo un firmante que el store confirma como
+  `role == "admin"` activo pasa, cualquier otro recibe 403 (encima de la firma+nonce+TLS
+  ya existentes). La CLI `membershipd user add --store kv` sigue existiendo SOLO para
+  sembrar el admin #0 (bootstrap del huevo-gallina: sin un admin sembrado no hay quién
+  firme el primer `POST /users`); a partir de ahí toda la gestión es HTTP admin-only. El
+  alta es idempotente igual que la CLI: re-alta de una clave ya registrada = 409, sin
+  sobrescribir ni elevar rol; el revoke es un flip de status (sin hard-delete), auditable.
+- **Cuentas estilo WhatsApp: alta por invitación, baja por hard-delete.** Sobre la API
+  admin anterior, `unibus` añade el modelo wallet de cuentas. El admin NO genera claves:
+  `POST /invites` (admin-only) acuña un enlace de invitación de un solo uso con caducidad
+  (token de 32 bytes `crypto/rand` en hex; TTL default 7 días), fijando `handle` y `role`.
+  El nuevo usuario abre el enlace en SU cliente, que genera el par de claves localmente
+  (la privada nunca sale del dispositivo) y llama `POST /register` con `{token, sign_pub,
+  kex_pub}`. `/register` es la ÚNICA ruta que añade al allowlist sin firma admin —
+  autorizada por el TOKEN, porque la identidad nueva aún no está en el allowlist y no puede
+  firmar. Está endurecida: token fuerte de un solo uso (consumo atómico, doble uso → 409),
+  caducidad (→ 410), `handle`/`role` fijados por el invite (sin escalado), validación
+  estricta de ambas claves hex de 64 chars, y rate-limit por IP heredado del control plane
+  (solo `/healthz` está exento). El borrado de cuenta es `DELETE /users/{signpub}`
+  (admin-only): hard-delete real del allowlist, distinto del `revoke` (que se mantiene:
+  revoke = quitar acceso dejando rastro auditable; delete = purga). Tras hard-delete, las
+  membresías de rooms del ex-usuario quedan inertes (ya no puede autenticarse en ningún
+  plano); NO se limpian a medias — un owner expulsa/rekey su room si quiere forward secrecy.
+  Invites y users viven en el MISMO store (SQLite `invites`/`users`, KV `UNIBUS_invites`/
+  `UNIBUS_users`). `pkg/client` gana `CreateInvite/ListInvites/CancelInvite/Register/
+  DeleteUser`; solo `Register` va sin firmar. Recovery: hard-delete del último admin se
+  recupera con la CLI local `membershipd user add` (mismo seam que siembra el admin #0).
 - **Identidad = secreto crítico.** El archivo de identidad (`worker.id`,
   `chat.id`) contiene las claves privadas (Ed25519 + X25519). Se escribe 0600.
   Perderlo = mensajes ilegibles, sin recuperación. Trátalo como una clave SSH.
@@ -154,6 +189,77 @@ agent.<nombre>.{in,out}   inbox/outbox de agente LLM (agent.scout.in)
 
 ## Capability growth log
 
+- v0.12.0 (2026-06-07) — capa de CUENTAS estilo WhatsApp sobre el modelo wallet: alta de
+  usuario por enlace de invitación de un solo uso + baja por hard-delete real. El admin
+  nunca ve la clave privada del usuario. (1) **Invites**: nuevo backend de datos en ambos
+  stores (SQLite `invites` vía migración aditiva `003_invites.sql`; KV `UNIBUS_invites`).
+  Tipo `Invite{Token, Handle, Role, ExpiresAt, Used, CreatedAt}` + campos de auditoría del
+  consumo (`UsedAt/UsedSignPub/UsedKexPub`). Métodos `Store.CreateInvite` (token 32 bytes
+  `crypto/rand` hex, TTL default 7d), `GetInvite`, `ListInvites`, `ConsumeInvite` (valida
+  existe/no-usado/no-caducado → registra el sign_pub con el handle/role del invite → marca
+  usado, atómico) y `CancelInvite`. Consumo single-use garantizado en ambos backends: tx
+  SQLite (mark guard `used=0` + insert) y CAS sobre la revisión KV (mark-first); burn-on-
+  claim idéntico si la clave ya existe. (2) **Hard-delete**: `Store.DeleteUser` (SQLite
+  `DELETE FROM users`, KV `users.Delete`) purga el allowlist — distinto del `revoke`
+  (status flip, conservado). Las membresías de rooms del ex-usuario quedan inertes
+  (documentado, sin limpieza parcial). (3) **Endpoints HTTP**: `POST /invites`, `GET
+  /invites` (solo pendientes), `DELETE /invites/{token}`, `DELETE /users/{signpub}`
+  (todos admin-only vía `requireAdmin`) y `POST /register` — la única ruta auth-exempt de
+  firma admin (autorizada por el token), rate-limited (se separa `isRateExempt`, solo
+  `/healthz`, de `isAuthExempt`) y con validación hex estricta de `sign_pub`+`kex_pub`
+  ANTES de gastar el token. Errores mapeados: token desconocido 404, usado 409, caducado
+  410, identidad ya registrada 409. (4) **pkg/client**: `CreateInvite/ListInvites/
+  CancelInvite/Register/DeleteUser`; `Register` va sin firma vía un helper `doUnsigned`.
+  (5) Fix de consistencia: el `GetUser` de SQLite ahora mapea `sql.ErrNoRows` → `ErrNotFound`
+  como el KV y como documenta `store.go`. Tests nuevos: suite de invites store-level en
+  AMBOS backends (golden + single-use + token desconocido + caducado + cancel + hard-delete
+  + burn-on-claim), suite HTTP (crear invite → register sin auth → aparece en allowlist →
+  re-register 409 → caducado 410 → no-admin 403 en las 4 rutas admin → hard-delete purga),
+  y test de cliente end-to-end (admin acuña invite → joiner no-registrado redime sin firma →
+  aparece → hard-delete desaparece). Cambios 100% aditivos: el comportamiento previo no
+  cambia; build/vet/test verdes (`CGO_ENABLED=0`).
+- v0.11.0 (2026-06-07) — flag dedicado `UNIBUS_NATS_MONITOR` que abre el endpoint
+  de monitoring HTTP del nats-server embebido (`127.0.0.1:8222`, loopback only) de
+  forma DESACOPLADA del debug-log. Antes el monitoring solo se abría con
+  `UNIBUS_NATS_DEBUG=1`, que además encendía el log verboso del nats-server
+  (rutas/RAFT/subjects a journald en claro) — incompatible con el endurecimiento
+  del issue 0007. El cómputo de los toggles se extrae a una función pura
+  `natsLogOpts(debugEnv, monitorEnv) (noLog, debug, trace, monitor)`: `MONITOR=1`
+  abre el endpoint dejando el log en silencio (`NoLog` true / `Debug` false), y se
+  mantiene el acoplamiento inverso por compatibilidad (`DEBUG` sigue implicando
+  `MONITOR`). El bind loopback `127.0.0.1` queda hardcoded — el monitoring NUNCA es
+  público y no lleva auth; lo lee un scraper local que empuja a VictoriaMetrics
+  (dashboard `unibus-nats` en `fleet_monitoring`). Se versiona el cableado de
+  deploy: drop-in systemd aditivo `membershipd-cluster.service.d/nats-monitor.conf`
+  (`Environment=UNIBUS_NATS_MONITOR=1`) + sección "NATS server metrics" en el
+  README del cluster con el runbook de activación rolling (magnus→homer→datardos)
+  y gate de reconvergencia R3 (`followers 2/2`) entre nodos. Tests nuevos: tabla
+  pura del desacoplamiento (monitor on ⇒ log NO debug; debug ⇒ monitor; default
+  cerrado) + server real con `MONITOR=1` que confirma `/varz` 200 en loopback:8222
+  y server sin flag con el endpoint cerrado. Cambios 100% aditivos: sin el flag el
+  comportamiento es idéntico; build/test verdes.
+- v0.10.0 (2026-06-07) — API HTTP admin-only de gestión de usuarios, cerrando la
+  última asimetría del control plane: las rooms tenían superficie HTTP firmada
+  (`POST /rooms`, etc.) pero los users solo se gestionaban por CLI local o acceso
+  directo al store. Se añaden `GET /users` (lista completa, incluidos revocados),
+  `POST /users` (alta `{sign_pub, handle, role}`: valida hex de 64 chars + role en
+  `{admin, member}`, 409 idempotente que no sobrescribe ni eleva rol) y
+  `POST /users/{signpub}/revoke` (flip de status, sin hard-delete). Los tres pasan por
+  un helper `requireAdmin` default-deny que confirma contra el store que el firmante
+  autenticado es un user `role == "admin"` activo (el endpoint id es un hash one-way de
+  la clave, así que el contexto lleva ahora también el `sign_pub` hex del firmante para
+  resolver `GetUser`); cualquier otro firmante recibe 403, encima de la firma+nonce+TLS+
+  enforce ya heredadas del middleware. NO se abre conexión KV nueva ni se usa la identidad
+  interna: el server escribe vía su `s.store` privilegiado, el MISMO que las rooms (SQLite
+  single-node, KV `UNIBUS_users` en cluster). `pkg/client` gana `ListUsers/AddUser/RevokeUser`
+  (tipo plano `UserInfo`) firmando como admin, así la pestaña Users del panel deja de
+  necesitar `--db`/acceso KV directo. La CLI `membershipd user add --store kv` queda SOLO
+  para sembrar el admin #0 (bootstrap). La validación de `sign_pub` se unifica en
+  `membership.ValidateSignPubHex`, reusada por la CLI y los handlers. Tests nuevos:
+  no-admin → 403 en los tres endpoints, roundtrip admin add→list→revoke, y validación
+  (hex inválido → 400, role inválido → 400, re-alta → 409), más un test de cliente contra
+  un membershipd embebido. Cambios 100% aditivos: el comportamiento single-node y de las
+  rutas de rooms no cambia; vet/build/test verdes.
 - v0.9.0 (2026-06-07) — cierre de los gaps que el despliegue del cluster (report
   0011) dejó abiertos (report 0012). (GAP A) Nueva capability `membershipd user
   add|list|revoke --store kv`: alta/baja de usuarios contra el KV replicado del

cmd/membershipd/users_cli.go

@@ -1,7 +1,6 @@
 package main
 
 import (
-	"encoding/hex"
 	"errors"
 	"flag"
 	"fmt"
@@ -90,16 +89,10 @@ func openStore(path string) membership.Store {
 
 // validateSignPubHex ensures the key is exactly a 32-byte Ed25519 public key in
 // hex (64 hex chars). Catching this here turns a silent "authorized nobody" into
-// an explicit error at seed time.
+// an explicit error at seed time. It delegates to membership.ValidateSignPubHex
+// so the CLI and the HTTP user-management handlers share one rule.
 func validateSignPubHex(signPub string) error {
-	b, err := hex.DecodeString(signPub)
-	if err != nil {
-		return fmt.Errorf("sign-pub is not valid hex: %w", err)
-	}
-	if len(b) != 32 {
-		return fmt.Errorf("sign-pub must be a 32-byte Ed25519 public key (64 hex chars), got %d bytes", len(b))
-	}
-	return nil
+	return membership.ValidateSignPubHex(signPub)
 }
 
 // kvFlags holds the connection flags shared by the --store kv path of the user

deploy/cluster/README.md

@@ -283,3 +283,61 @@ ssh dd 'sudo systemctl start membershipd-cluster'   # rejoins, catches up
 the unit and start it without `--store kv`/`--cluster-name`; the KV buckets remain
 for a later retry. To rotate the cluster CA, re-run `generate-cluster-certs.sh
 --force` and re-stage (every node must get the new `cluster-ca.crt` together).
+
+## NATS server metrics (loopback monitoring — optional)
+
+The embedded NATS server can expose its own monitoring HTTP endpoint so a local
+scraper reads server-level metrics that `/healthz` does not surface: msgs/s,
+connections, slow consumers, memory, KV bucket message counts, the RAFT leader per
+stream and per-stream restarts. This feeds the `unibus-nats` dashboard in
+`fleet_monitoring` (the scraper hits `127.0.0.1:8222/varz|/connz|/jsz` over
+loopback and pushes to VictoriaMetrics).
+
+The endpoint is opened by the **dedicated** environment toggle `UNIBUS_NATS_MONITOR=1`
+(0.11.0+ binary). It is **decoupled** from `UNIBUS_NATS_DEBUG`: it opens the
+monitoring endpoint WITHOUT enabling the verbose nats-server debug log, so no room
+subjects or routing metadata leak to journald (keeps the hardened posture, issue
+0007). The endpoint binds `127.0.0.1:8222` **only** — the binary hardcodes the
+loopback bind, so it is never reachable from the network and needs no auth. Never
+use `UNIBUS_NATS_DEBUG` in production just to get the endpoint.
+
+### Enable it (HUMAN — requires the 0.11.0+ binary on the node)
+
+The clean way is the additive systemd drop-in in this directory:
+
+```bash
+# On each node, AFTER the 0.11.0+ binary is in /opt/unibus/membershipd:
+ssh <node> 'sudo mkdir -p /etc/systemd/system/membershipd-cluster.service.d'
+scp membershipd-cluster.service.d/nats-monitor.conf <node>:/tmp/nats-monitor.conf
+ssh <node> 'sudo cp /tmp/nats-monitor.conf /etc/systemd/system/membershipd-cluster.service.d/ \
+  && sudo systemctl daemon-reload && sudo systemctl restart membershipd-cluster'
+```
+
+(Equivalently, add `UNIBUS_NATS_MONITOR=1` to `/opt/unibus/cluster.env`, which the
+unit already sources via `EnvironmentFile`; the drop-in is preferred because it is
+self-documenting and does not edit the generated env file.)
+
+### Rolling restart with the R3 reconvergence gate (CRITICAL)
+
+`systemctl restart membershipd-cluster` restarts that node's JetStream RAFT member.
+**Never restart two nodes at once** — that would drop the cluster below quorum
+(2/3) and fail the control plane closed. Roll **one node at a time**, in the order
+`magnus → homer → datardos`, and between each node wait until the cluster has
+reconverged to R3 (every control-plane bucket back to `followers_current=2/2`):
+
+```bash
+# After restarting ONE node, gate on R3 reconvergence before touching the next:
+ssh root@magnus 'for s in KV_UNIBUS_users KV_UNIBUS_rooms KV_UNIBUS_members \
+  KV_UNIBUS_room_keys KV_UNIBUS_rooms_by_member KV_UNIBUS_nonces; do
+    nats --server nats://127.0.0.1:4250 stream info "$s" -j \
+      | jq -r --arg s "$s" \"\\($s): replicas=\\(.cluster.replicas|length) leader=\\(.cluster.leader)\"
+  done'
+# Proceed to the next node ONLY when all six show 3 replicas with a leader
+# (i.e. 2/2 followers current). Also confirm healthz is green on the just-restarted
+# node first:
+ssh <node> 'curl -fsS https://127.0.0.1:8470/healthz --cacert /opt/unibus/tls/ca.crt'
+```
+
+This restart is normally **not** done as a standalone step: the 0.11.0 binary that
+carries the flag is rolled to the three nodes in the consolidated rollout, and the
+drop-in is installed during that same rolling restart.

deploy/cluster/membershipd-cluster.service.d/nats-monitor.conf

@@ -0,0 +1,27 @@
+# Drop-in: enable the embedded NATS server monitoring HTTP endpoint so a local
+# metrics scraper can read /varz, /connz and /jsz for server-level metrics
+# (msgs/s, connections, KV bucket msgs, RAFT leader per stream, restarts).
+#
+# ADDITIVE and minimal: it only sets one environment variable; the base unit
+# (membershipd-cluster.service) is otherwise unchanged.
+#
+# UNIBUS_NATS_MONITOR is DECOUPLED from UNIBUS_NATS_DEBUG: it opens the monitoring
+# endpoint WITHOUT enabling the verbose nats-server debug log, so no room subjects
+# or routing metadata are written to journald (keeps the hardened posture, issue
+# 0007). Do NOT use UNIBUS_NATS_DEBUG in production just to get the endpoint.
+#
+# The endpoint binds 127.0.0.1:8222 ONLY — the binary hardcodes the loopback bind,
+# so it is never reachable from the network and needs no auth. The scraper runs on
+# the same host and reads it over loopback.
+#
+# Requires the 0.11.0+ membershipd binary (the one that honors UNIBUS_NATS_MONITOR).
+# Install on a node:
+#   sudo mkdir -p /etc/systemd/system/membershipd-cluster.service.d
+#   sudo cp nats-monitor.conf /etc/systemd/system/membershipd-cluster.service.d/
+#   sudo systemctl daemon-reload && sudo systemctl restart membershipd-cluster
+#
+# Restarting a node restarts its JetStream RAFT member, so roll ONE node at a time
+# and wait for R3 reconvergence (followers 2/2) before touching the next. See the
+# "NATS server metrics" section of this directory's README for the full runbook.
+[Service]
+Environment=UNIBUS_NATS_MONITOR=1

dev/issues/0007-jetstream-encryption-at-rest.md

@@ -0,0 +1,78 @@
+---
+issue: 0007
+title: Cifrado at-rest del control plane (JetStream KV / SQLite en disco)
+status: spec
+created: 2026-06-07
+domain: security
+scope: unibus (pkg/embeddednats, cmd/membershipd, deploy/cluster) + procedimiento de migración del store existente
+---
+
+# Objetivo
+
+Cifrar en reposo el almacenamiento del plano de control para que un nodo comprometido
+(root en el VPS) o un disco robado no exponga los metadatos de control en claro.
+
+Estado actual (auditado el 07/06/2026, report 0012 y siguientes):
+
+- **Contenido de los mensajes**: cifrado E2E por room (megolm/olm). El servidor nunca ve el
+  plaintext; no vive en el plano de control. **No es el objeto de este issue.**
+- **Claves de room** (`UNIBUS_room_keys`): guardadas **selladas** (sealed box X25519, cifradas
+  para cada miembro). El servidor las almacena y reparte pero no puede abrirlas. **Ya protegidas.**
+- **Metadatos de control** (`UNIBUS_rooms`, `UNIBUS_members`, `UNIBUS_rooms_by_member`,
+  `UNIBUS_users`): se serializan con `json.Marshal` y se escriben **en claro** en el store. En
+  cluster ese store es el directorio `local_files/jetstream/` de cada nodo; en single-node es el
+  archivo SQLite `local_files/unibus.db`. Hoy **no hay cifrado at-rest**: con root en un nodo se
+  pueden leer subjects de salas, la pertenencia (quién está en qué sala con qué rol), los handles
+  y roles de los usuarios, y las claves públicas (signPub/kexPub). No se exponen mensajes (E2E) ni
+  se pueden descifrar salas (claves selladas), pero sí toda la topología.
+
+Tras este issue, los buckets/archivos del control plane quedan cifrados en disco con una clave por
+nodo gestionada fuera de git. El modelo de amenaza pasa de "root del nodo ve la topología" a "root
+del nodo necesita además la clave at-rest (que puede vivir en un secreto separado / TPM / variable
+de entorno inyectada) para leer cualquier cosa".
+
+# Contexto técnico
+
+- NATS Server / JetStream soporta **encryption at-rest** nativo: se configura una cifra
+  (`aes` o `chacha20`) y una clave; JetStream cifra los ficheros de los streams/KV en disco. El
+  bus usa un NATS **embebido** (`pkg/embeddednats`), así que la activación es por opciones del
+  servidor embebido, no por un `nats-server.conf` externo.
+- Para el backend SQLite (single-node) el equivalente sería SQLCipher o cifrado a nivel de
+  archivo/FS; queda como sub-tarea de menor prioridad porque el despliegue real es cluster (KV).
+
+# Tareas
+
+1. Confirmar la API de encryption-at-rest del NATS embebido en la versión usada (opción de
+   servidor para cipher + clave; cómo se pasa la clave de forma que no quede en argv ni en git).
+2. Activar el cifrado en `pkg/embeddednats` detrás de una opción de configuración. La clave se
+   inyecta por archivo (`--jetstream-encryption-key-file`, 0600, junto a las claves TLS del nodo)
+   o variable de entorno desde el unit systemd; nunca en argv ni commiteada.
+3. `cmd/membershipd`: flag/env para la clave + reflejar el estado en la posture publicada en
+   `/healthz` (p.ej. `"at_rest":true`) para que el monitor lo verifique.
+4. `deploy/cluster`: provisionar la clave at-rest por nodo (generación + `pass`/secrets gitignored)
+   y cablearla en `cluster.env` + el unit. Documentar en el runbook.
+5. **Migración del store existente** (gotcha crítico): JetStream no re-cifra retroactivamente los
+   datos ya escritos en claro. Diseñar y documentar el procedimiento seguro para el cluster en
+   producción (probable: backup → exportar snapshot del control plane → parar nodo → recrear el
+   store con la clave activa → re-importar; o rotación nodo a nodo aprovechando la replicación R3).
+   Respetar la regla de migraciones (aditivo, sin pérdida de datos).
+6. Tests: arrancar un nodo con clave at-rest, escribir un user/room, y verificar que el fichero en
+   disco **no** contiene en claro un subject/handle conocido (grep negativo), y que el nodo sigue
+   leyéndolos con la clave. Verificar que sin la clave el store no se abre.
+
+# Definition of Done
+
+- Cifrado at-rest activo en los 3 nodos del cluster; `/healthz` lo refleja en la posture.
+- Evidencia ejecutable: un valor conocido (subject de sala / handle de usuario) **no** aparece en
+  claro al hacer `grep` sobre `local_files/jetstream/`; el nodo lo sigue sirviendo con la clave.
+- Procedimiento de migración probado sobre datos reales sin pérdida (snapshot/restore verificado).
+- La clave at-rest nunca está en git ni en argv; vive en archivo 0600 / secreto inyectado.
+- No baja ninguna otra capa de seguridad (enforce + ACL + TLS + E2E + sealed keys intactas).
+
+# Notas
+
+Aditivo y ortogonal al resto de la seguridad: TLS protege en tránsito, E2E el contenido, las claves
+de room van selladas; este issue cierra el último hueco (metadatos de control en claro en disco)
+para el modelo de amenaza "VPS comprometido / disco robado". Prioridad media: el despliegue ya es
+seguro frente a ataques de red (enforce+TLS+ACL); esto endurece frente a compromiso físico/root del
+host. Relacionado con el endurecimiento de los issues 0004/0005/0006.

migrations/003_invites.sql

@@ -0,0 +1,28 @@
+-- 003_invites.sql — single-use registration invites (issue: user accounts / wallet model).
+--
+-- An admin mints an invite so a brand-new identity can join the bus allowlist
+-- WITHOUT the admin ever handling its private key. The token is the bearer
+-- secret that authorizes POST /register: the registering client generates its
+-- keypair locally and publishes only its public keys, fixing the link between an
+-- invite and the identity it creates via the audit columns below. The handle and
+-- role are fixed by the admin at mint time and cannot be changed by the client
+-- (no privilege escalation).
+--
+-- Additive and idempotent: safe to apply repeatedly. Never modify this file;
+-- further schema changes go in new numbered migrations (see
+-- .claude/rules/db_migrations.md). The embedded copy under
+-- pkg/membership/migrations/003_invites.sql mirrors this file byte-for-byte.
+
+CREATE TABLE IF NOT EXISTS invites (
+  token         TEXT PRIMARY KEY,                -- 32 random bytes in lowercase hex (the bearer secret)
+  handle        TEXT NOT NULL,                   -- handle the new user will get (fixed by admin)
+  role          TEXT NOT NULL DEFAULT 'member',  -- 'admin' | 'member' (fixed by admin)
+  expires_at    TEXT NOT NULL,                   -- RFC3339; past this the invite is dead
+  used          INTEGER NOT NULL DEFAULT 0,      -- 0 pending, 1 consumed (single-use)
+  created_at    TEXT NOT NULL,
+  used_at       TEXT,                            -- RFC3339 when consumed (NULL until used)
+  used_sign_pub TEXT,                            -- Ed25519 key that consumed it (audit; NULL until used)
+  used_kex_pub  TEXT                             -- X25519 key presented at registration (audit; NULL until used)
+);
+
+CREATE INDEX IF NOT EXISTS idx_invites_used ON invites(used);

pkg/client/client.go

@@ -331,6 +331,60 @@ func (c *Client) doJSON(method, path string, body, out any) error {
 	return fmt.Errorf("client: %s %s: all control planes failed: %w", method, path, lastErr)
 }
 
+// doUnsigned performs a control-plane request WITHOUT the transport signature
+// headers, for the one endpoint a not-yet-registered identity must reach: POST
+// /register. The registering peer is not in the allowlist, so it cannot produce
+// an accepted signature; authorization is the single-use invite token inside the
+// body. Like doJSON it fails over across the control-plane endpoints (any node
+// serves the same state) and surfaces the server's structured error message.
+func (c *Client) doUnsigned(method, path string, body, out any) error {
+	var bodyBytes []byte
+	if body != nil {
+		b, err := json.Marshal(body)
+		if err != nil {
+			return fmt.Errorf("client: marshal request: %w", err)
+		}
+		bodyBytes = b
+	}
+	var lastErr error
+	for _, base := range c.ctrlURLs {
+		var rdr io.Reader
+		if bodyBytes != nil {
+			rdr = bytes.NewReader(bodyBytes)
+		}
+		req, err := http.NewRequest(method, base+path, rdr)
+		if err != nil {
+			return fmt.Errorf("client: new request: %w", err)
+		}
+		if body != nil {
+			req.Header.Set("Content-Type", "application/json")
+		}
+		resp, err := c.http.Do(req)
+		if err != nil {
+			lastErr = err
+			continue // dead node: try the next control plane
+		}
+		defer resp.Body.Close()
+		respBody, _ := io.ReadAll(resp.Body)
+		if resp.StatusCode >= 300 {
+			var er struct {
+				Error string `json:"error"`
+			}
+			if json.Unmarshal(respBody, &er) == nil && er.Error != "" {
+				return fmt.Errorf("%s (HTTP %d)", er.Error, resp.StatusCode)
+			}
+			return fmt.Errorf("client: %s %s -> %d: %s", method, path, resp.StatusCode, string(respBody))
+		}
+		if out != nil {
+			if err := json.Unmarshal(respBody, out); err != nil {
+				return fmt.Errorf("client: decode response: %w", err)
+			}
+		}
+		return nil
+	}
+	return fmt.Errorf("client: %s %s: all control planes failed: %w", method, path, lastErr)
+}
+
 // signRequest signs the canonical bytes of req (req must already have its Sig
 // field cleared) with the client's Ed25519 key. It is symmetric with the
 // server's verifyOwnerSig. This is the PAYLOAD-level owner signature that
@@ -456,6 +510,52 @@ type memberRoomJSON struct {
 	Role    string     `json:"role"`
 }
 
+// userJSON mirrors the server's wire type on the admin user-management endpoints.
+type userJSON struct {
+	SignPub   string `json:"sign_pub"`
+	Handle    string `json:"handle"`
+	Role      string `json:"role"`
+	Status    string `json:"status"`
+	CreatedAt string `json:"created_at"`
+	RevokedAt string `json:"revoked_at,omitempty"`
+}
+
+// addUserReq is the POST /users body (mirror of the server type).
+type addUserReq struct {
+	SignPub string `json:"sign_pub"`
+	Handle  string `json:"handle"`
+	Role    string `json:"role"`
+}
+
+// createInviteReq / createInviteResp mirror the server's POST /invites types.
+type createInviteReq struct {
+	Handle  string `json:"handle"`
+	Role    string `json:"role"`
+	TTLSecs int    `json:"ttl_secs"`
+}
+
+type createInviteResp struct {
+	Token     string `json:"token"`
+	ExpiresAt string `json:"expires_at"`
+}
+
+// inviteJSON mirrors the server's GET /invites row.
+type inviteJSON struct {
+	Token     string `json:"token"`
+	Handle    string `json:"handle"`
+	Role      string `json:"role"`
+	ExpiresAt string `json:"expires_at"`
+	Used      bool   `json:"used"`
+	CreatedAt string `json:"created_at"`
+}
+
+// registerReq mirrors the server's POST /register body.
+type registerReq struct {
+	Token   string `json:"token"`
+	SignPub string `json:"sign_pub"`
+	KexPub  string `json:"kex_pub"`
+}
+
 // ---- room operations ------------------------------------------------------
 
 // RoomRef is a room this peer belongs to, returned by ListMyRooms. It is the
@@ -490,6 +590,135 @@ func (c *Client) ListMyRooms() ([]RoomRef, error) {
 	return out, nil
 }
 
+// ---- user administration (admin-only) ------------------------------------
+
+// UserInfo is a bus user as returned by the admin user-management endpoints. It
+// is a flat view (no nested types) for the admin panel: the signing key
+// (lowercase hex), handle, role ("admin"|"member"), status ("active"|"revoked"),
+// and timestamps. RevokedAt is empty for an active user.
+type UserInfo struct {
+	SignPub   string
+	Handle    string
+	Role      string
+	Status    string
+	CreatedAt string
+	RevokedAt string
+}
+
+// ListUsers returns the full bus allowlist, including revoked users. The caller
+// must be signing as an admin: a non-admin signer is rejected by the server with
+// 403, surfaced here as an error.
+func (c *Client) ListUsers() ([]UserInfo, error) {
+	var resp []userJSON
+	if err := c.doJSON("GET", "/users", nil, &resp); err != nil {
+		return nil, err
+	}
+	out := make([]UserInfo, 0, len(resp))
+	for _, u := range resp {
+		out = append(out, UserInfo{
+			SignPub:   u.SignPub,
+			Handle:    u.Handle,
+			Role:      u.Role,
+			Status:    u.Status,
+			CreatedAt: u.CreatedAt,
+			RevokedAt: u.RevokedAt,
+		})
+	}
+	return out, nil
+}
+
+// AddUser registers a bus user from their Ed25519 signing public key (64-hex).
+// role is "admin" or "member" (empty defaults to member, matching the server).
+// The caller must be signing as an admin. Re-adding an already-registered key
+// returns an error (the server replies 409 and leaves the existing row
+// untouched — no silent role/status change).
+func (c *Client) AddUser(signPub, handle, role string) error {
+	return c.doJSON("POST", "/users", addUserReq{SignPub: signPub, Handle: handle, Role: role}, nil)
+}
+
+// RevokeUser revokes a bus user by their signing public key (64-hex). Revocation
+// is a status flip (no hard delete): the identity stays auditable and is denied
+// on both planes immediately. The caller must be signing as an admin.
+func (c *Client) RevokeUser(signPub string) error {
+	return c.doJSON("POST", "/users/"+signPub+"/revoke", nil, nil)
+}
+
+// DeleteUser hard-deletes a bus user by their signing public key (64-hex) — the
+// purge counterpart of RevokeUser. The allowlist row is removed entirely (no
+// audit trail); the ex-user can no longer authenticate, so their room
+// memberships become inert. The caller must be signing as an admin.
+func (c *Client) DeleteUser(signPub string) error {
+	return c.doJSON("DELETE", "/users/"+signPub, nil, nil)
+}
+
+// InviteInfo is a single-use registration invite as returned by the admin invite
+// endpoints. It is a flat view for the admin panel: the bearer token (to build
+// the join link), the handle and role the new user will receive, the absolute
+// expiry, whether it has been used, and when it was minted.
+type InviteInfo struct {
+	Token     string
+	Handle    string
+	Role      string
+	ExpiresAt string
+	Used      bool
+	CreatedAt string
+}
+
+// CreateInvite mints a single-use registration invite. handle and role are fixed
+// here (the registering client cannot change them); role is "admin" or "member"
+// (empty defaults to member). ttlSecs sets the link lifetime (non-positive uses
+// the server's 7-day default). The returned InviteInfo carries the token and
+// expiry; the caller turns the token into a join link. Caller must sign as admin.
+func (c *Client) CreateInvite(handle, role string, ttlSecs int) (InviteInfo, error) {
+	var resp createInviteResp
+	if err := c.doJSON("POST", "/invites", createInviteReq{Handle: handle, Role: role, TTLSecs: ttlSecs}, &resp); err != nil {
+		return InviteInfo{}, err
+	}
+	r := role
+	if r == "" {
+		r = "member"
+	}
+	return InviteInfo{Token: resp.Token, Handle: handle, Role: r, ExpiresAt: resp.ExpiresAt}, nil
+}
+
+// ListInvites returns the pending invites (not used, not expired). Caller must
+// sign as admin.
+func (c *Client) ListInvites() ([]InviteInfo, error) {
+	var resp []inviteJSON
+	if err := c.doJSON("GET", "/invites", nil, &resp); err != nil {
+		return nil, err
+	}
+	out := make([]InviteInfo, 0, len(resp))
+	for _, inv := range resp {
+		out = append(out, InviteInfo{
+			Token:     inv.Token,
+			Handle:    inv.Handle,
+			Role:      inv.Role,
+			ExpiresAt: inv.ExpiresAt,
+			Used:      inv.Used,
+			CreatedAt: inv.CreatedAt,
+		})
+	}
+	return out, nil
+}
+
+// CancelInvite cancels (deletes) a pending invite by its token, so an admin can
+// revoke a link before it is redeemed. Caller must sign as admin.
+func (c *Client) CancelInvite(token string) error {
+	return c.doJSON("DELETE", "/invites/"+token, nil, nil)
+}
+
+// Register redeems a single-use invite token, joining the bus allowlist. It is
+// the wallet-model join call: the registering peer generated its own keypair
+// locally and publishes ONLY its public keys here (signPub Ed25519, kexPub
+// X25519, both 64-hex). It is UNSIGNED — the bearer token is the authorization,
+// because this identity is not yet in the allowlist and so cannot sign an
+// accepted request. On success the identity is registered with the invite's
+// handle and role and can connect like any other peer.
+func (c *Client) Register(token, signPub, kexPub string) error {
+	return c.doUnsigned("POST", "/register", registerReq{Token: token, SignPub: signPub, KexPub: kexPub}, nil)
+}
+
 // newRoomKey returns 32 random bytes for a symmetric room key.
 func newRoomKey() ([]byte, error) {
 	k := make([]byte, 32)

pkg/client/invites_test.go

@@ -0,0 +1,104 @@
+package client_test
+
+import (
+	"encoding/hex"
+	"testing"
+
+	"github.com/enmanuel/unibus/pkg/client"
+	"github.com/enmanuel/unibus/pkg/membership"
+)
+
+// TestClientInvitesAdminAPI drives the wallet-model account flow through the real
+// pkg/client methods against an in-process membershipd under enforce: an admin
+// mints an invite, a brand-new identity redeems it via the UNSIGNED Register call
+// (it is not yet in the allowlist), the admin then sees the user, and finally the
+// admin hard-deletes it and it vanishes. This is the exact path the admin panel +
+// the /join client page depend on, so it locks the client/server contract.
+func TestClientInvitesAdminAPI(t *testing.T) {
+	h := newHarnessMode(t, membership.AuthEnforce)
+	waitHealth(t, h.ctrlURL)
+
+	admin, err := client.New(h.natsURL, h.ctrlURL, mustIdentity(t))
+	if err != nil {
+		t.Fatalf("connect admin: %v", err)
+	}
+	defer admin.Close()
+	registerClient(t, h, admin, "admin", membership.RoleAdmin)
+
+	// Admin mints a single-use invite fixing handle + role.
+	inv, err := admin.CreateInvite("dora", membership.RoleMember, 0)
+	if err != nil {
+		t.Fatalf("admin CreateInvite: %v", err)
+	}
+	if len(inv.Token) != 64 || inv.ExpiresAt == "" {
+		t.Fatalf("invite malformed: %+v", inv)
+	}
+	if inv.Handle != "dora" || inv.Role != membership.RoleMember {
+		t.Fatalf("invite echo wrong: %+v", inv)
+	}
+
+	// It appears among the pending invites.
+	pend, err := admin.ListInvites()
+	if err != nil {
+		t.Fatalf("admin ListInvites: %v", err)
+	}
+	if !containsToken(pend, inv.Token) {
+		t.Fatalf("minted invite not pending: %+v", pend)
+	}
+
+	// A brand-new identity (NOT in the allowlist) redeems the invite via the
+	// UNSIGNED Register. We model its locally-generated keypair with a fresh
+	// identity and present its two public keys. Redeeming through this joiner
+	// client — which never registered and never seeded an admin — proves Register
+	// needs no admin signature; the bearer token is the sole authorization.
+	newID := mustIdentity(t)
+	signPub := hex.EncodeToString(newID.SignPub)
+	kexPub := hex.EncodeToString(newID.KexPub)
+	joiner, err := client.New(h.natsURL, h.ctrlURL, newID)
+	if err != nil {
+		t.Fatalf("connect joiner: %v", err)
+	}
+	defer joiner.Close()
+	if err := joiner.Register(inv.Token, signPub, kexPub); err != nil {
+		t.Fatalf("joiner Register: %v", err)
+	}
+
+	// Admin now sees dora in the allowlist with the invite's handle/role.
+	users, err := admin.ListUsers()
+	if err != nil {
+		t.Fatalf("admin ListUsers: %v", err)
+	}
+	row, ok := findUserInfo(users, signPub)
+	if !ok {
+		t.Fatalf("registered dora missing from allowlist: %+v", users)
+	}
+	if row.Handle != "dora" || row.Role != membership.RoleMember || row.Status != membership.StatusActive {
+		t.Fatalf("dora row wrong: %+v", row)
+	}
+
+	// Single-use: redeeming again is an error.
+	if err := joiner.Register(inv.Token, signPub, kexPub); err == nil {
+		t.Fatalf("second Register should error (used token)")
+	}
+
+	// Admin hard-deletes dora; she vanishes from the allowlist entirely.
+	if err := admin.DeleteUser(signPub); err != nil {
+		t.Fatalf("admin DeleteUser: %v", err)
+	}
+	users, err = admin.ListUsers()
+	if err != nil {
+		t.Fatalf("admin ListUsers after delete: %v", err)
+	}
+	if _, ok := findUserInfo(users, signPub); ok {
+		t.Fatalf("hard-deleted dora must NOT appear: %+v", users)
+	}
+}
+
+func containsToken(invites []client.InviteInfo, token string) bool {
+	for _, i := range invites {
+		if i.Token == token {
+			return true
+		}
+	}
+	return false
+}

pkg/client/users_test.go

@@ -0,0 +1,99 @@
+package client_test
+
+import (
+	"encoding/hex"
+	"strings"
+	"testing"
+
+	"github.com/enmanuel/unibus/pkg/client"
+	"github.com/enmanuel/unibus/pkg/membership"
+)
+
+// findUserInfo returns the row with the given signing key (case-insensitive).
+func findUserInfo(users []client.UserInfo, signPub string) (client.UserInfo, bool) {
+	want := strings.ToLower(signPub)
+	for _, u := range users {
+		if strings.ToLower(u.SignPub) == want {
+			return u, true
+		}
+	}
+	return client.UserInfo{}, false
+}
+
+// TestClientUsersAdminAPI drives the admin user-management API through the real
+// pkg/client methods against an in-process membershipd under enforce: an admin
+// client adds a user, lists it, revokes it, and sees the status flip — and a
+// non-admin client is denied. This is the path the admin panel uses, so it locks
+// the client/server contract the panel depends on.
+func TestClientUsersAdminAPI(t *testing.T) {
+	h := newHarnessMode(t, membership.AuthEnforce)
+	waitHealth(t, h.ctrlURL)
+
+	admin, err := client.New(h.natsURL, h.ctrlURL, mustIdentity(t))
+	if err != nil {
+		t.Fatalf("connect admin: %v", err)
+	}
+	defer admin.Close()
+	registerClient(t, h, admin, "admin", membership.RoleAdmin)
+
+	member, err := client.New(h.natsURL, h.ctrlURL, mustIdentity(t))
+	if err != nil {
+		t.Fatalf("connect member: %v", err)
+	}
+	defer member.Close()
+	registerClient(t, h, member, "member", membership.RoleMember)
+
+	// A brand-new identity the admin will register over HTTP.
+	carol := mustIdentity(t)
+	carolPub := hex.EncodeToString(carol.SignPub)
+
+	// Admin adds carol as a member.
+	if err := admin.AddUser(carolPub, "carol", membership.RoleMember); err != nil {
+		t.Fatalf("admin AddUser: %v", err)
+	}
+
+	// Admin lists: carol present and active.
+	users, err := admin.ListUsers()
+	if err != nil {
+		t.Fatalf("admin ListUsers: %v", err)
+	}
+	row, ok := findUserInfo(users, carolPub)
+	if !ok {
+		t.Fatalf("carol missing from list after add: %+v", users)
+	}
+	if row.Status != membership.StatusActive || row.Role != membership.RoleMember {
+		t.Fatalf("carol row wrong after add: %+v", row)
+	}
+
+	// Re-adding the same key is a conflict surfaced as an error (no silent upsert).
+	if err := admin.AddUser(carolPub, "carol-again", membership.RoleAdmin); err == nil {
+		t.Fatalf("re-adding carol should error (409), got nil")
+	}
+
+	// Admin revokes carol; list shows the status flip (no hard delete).
+	if err := admin.RevokeUser(carolPub); err != nil {
+		t.Fatalf("admin RevokeUser: %v", err)
+	}
+	users, err = admin.ListUsers()
+	if err != nil {
+		t.Fatalf("admin ListUsers after revoke: %v", err)
+	}
+	row, ok = findUserInfo(users, carolPub)
+	if !ok {
+		t.Fatalf("carol vanished after revoke (should be a status flip): %+v", users)
+	}
+	if row.Status != membership.StatusRevoked {
+		t.Fatalf("carol should be revoked, got status %q", row.Status)
+	}
+
+	// A non-admin (member) is denied on every user-management method.
+	if _, err := member.ListUsers(); err == nil {
+		t.Fatalf("non-admin ListUsers should error (403), got nil")
+	}
+	if err := member.AddUser(carolPub, "x", membership.RoleMember); err == nil {
+		t.Fatalf("non-admin AddUser should error (403), got nil")
+	}
+	if err := member.RevokeUser(carolPub); err == nil {
+		t.Fatalf("non-admin RevokeUser should error (403), got nil")
+	}
+}

pkg/embeddednats/embeddednats.go

@@ -103,17 +103,38 @@ func StartHostAuth(storeDir, host string, port int, auth server.Authentication)
 	return StartServer(ServerConfig{StoreDir: storeDir, Host: host, Port: port, Auth: auth})
 }
 
+// natsLogOpts maps the two independent environment toggles to the embedded
+// nats-server logging and monitoring flags. It is a pure function (no I/O) so the
+// decoupling between the two toggles can be unit-tested directly.
+//
+//   - UNIBUS_NATS_DEBUG="1" enables the nats-server logger (route/RAFT/JetStream
+//     errors); "2" additionally enables protocol tracing. Off by default so the
+//     server stays silent (NoLog) and production behavior is unchanged.
+//   - UNIBUS_NATS_MONITOR="1" opens the monitoring HTTP endpoint (loopback only)
+//     for a local metrics scraper to read /varz, /connz and /jsz.
+//
+// The two are DECOUPLED on purpose: enabling the monitoring endpoint must NOT turn
+// on the verbose debug log, which would write room subjects and routing metadata
+// to journald in clear and regress the hardened posture (issue 0007). The reverse
+// coupling is kept for backward compatibility: debug mode still exposes the
+// monitoring endpoint as well (debug implies monitor), so existing debugging
+// workflows are unchanged.
+func natsLogOpts(debugEnv, monitorEnv string) (noLog, debug, trace, monitor bool) {
+	debug = debugEnv == "1" || debugEnv == "2"
+	trace = debugEnv == "2"
+	monitor = monitorEnv == "1" || debug
+	noLog = !debug
+	return noLog, debug, trace, monitor
+}
+
 // StartServer launches an embedded nats-server with JetStream from cfg. It
 // blocks until the server is ready to accept connections (up to 5s) and returns
 // the running server; the caller must Shutdown it.
 func StartServer(cfg ServerConfig) (*server.Server, error) {
-	// Diagnostic toggle: UNIBUS_NATS_DEBUG=1 enables the embedded nats-server's own
-	// logger (route/RAFT/JetStream errors), which is otherwise silenced. Off by
-	// default so production behavior is unchanged; only set it when debugging the
-	// cluster route layer.
-	debugLevel := os.Getenv("UNIBUS_NATS_DEBUG")
-	debugNATS := debugLevel == "1" || debugLevel == "2"
-	traceNATS := debugLevel == "2"
+	// Map the two independent env toggles to the nats-server logging + monitoring
+	// flags. See natsLogOpts for the decoupling rationale (issue 0007).
+	noLog, debugNATS, traceNATS, monitorNATS := natsLogOpts(
+		os.Getenv("UNIBUS_NATS_DEBUG"), os.Getenv("UNIBUS_NATS_MONITOR"))
 	opts := &server.Options{
 		JetStream:  true,
 		StoreDir:   cfg.StoreDir,
@@ -122,15 +143,17 @@ func StartServer(cfg ServerConfig) (*server.Server, error) {
 		ServerName: cfg.ServerName,
 		DontListen: false,
 		// Keep the embedded server quiet by default; the host app logs the URLs.
-		NoLog:   !debugNATS,
+		NoLog:   noLog,
 		Debug:   debugNATS,
 		Trace:   traceNATS,
 		Logtime: true,
 		NoSigs:  true,
 	}
-	if debugNATS {
-		// Expose the nats-server monitoring endpoint (loopback) so the operator can
-		// inspect /jsz, /routez, /varz while debugging the cluster meta-group.
+	if monitorNATS {
+		// Expose the nats-server monitoring endpoint on LOOPBACK ONLY (never public):
+		// the operator (or a local metrics scraper) inspects /varz, /connz, /jsz,
+		// /routez. The 127.0.0.1 bind is mandatory because this endpoint has no auth;
+		// it must stay unreachable from the network.
 		opts.HTTPHost = "127.0.0.1"
 		opts.HTTPPort = 8222
 	}

pkg/embeddednats/monitor_test.go

@@ -0,0 +1,134 @@
+package embeddednats
+
+import (
+	"io"
+	"net"
+	"net/http"
+	"testing"
+	"time"
+)
+
+// TestNatsLogOptsDecoupled is the core regression guard for issue 0007: turning
+// on the monitoring endpoint must NEVER turn on the verbose nats-server debug log
+// (which would leak room subjects/routing metadata to journald). It also checks
+// the backward-compatible coupling (debug still implies monitoring) and the quiet
+// default.
+func TestNatsLogOptsDecoupled(t *testing.T) {
+	cases := []struct {
+		name                         string
+		debugEnv, monitorEnv         string
+		noLog, debug, trace, monitor bool
+	}{
+		{"default off — quiet, no monitor", "", "", true, false, false, false},
+		{"monitor only — endpoint on, log stays quiet", "", "1", true, false, false, true},
+		{"debug implies monitor", "1", "", false, true, false, true},
+		{"trace implies debug+monitor", "2", "", false, true, true, true},
+		{"both set", "1", "1", false, true, false, true},
+		{"monitor garbage value ignored", "", "yes", true, false, false, false},
+		{"debug garbage value ignored", "true", "", true, false, false, false},
+	}
+	for _, c := range cases {
+		t.Run(c.name, func(t *testing.T) {
+			noLog, debug, trace, monitor := natsLogOpts(c.debugEnv, c.monitorEnv)
+			if noLog != c.noLog || debug != c.debug || trace != c.trace || monitor != c.monitor {
+				t.Fatalf("natsLogOpts(%q,%q) = (noLog=%v debug=%v trace=%v monitor=%v), want (noLog=%v debug=%v trace=%v monitor=%v)",
+					c.debugEnv, c.monitorEnv, noLog, debug, trace, monitor,
+					c.noLog, c.debug, c.trace, c.monitor)
+			}
+		})
+	}
+
+	// Explicit golden assertion of the security property: monitor on, log off.
+	noLog, debug, _, monitor := natsLogOpts("", "1")
+	if !monitor {
+		t.Fatal("UNIBUS_NATS_MONITOR=1 must open the monitoring endpoint")
+	}
+	if debug || !noLog {
+		t.Fatalf("UNIBUS_NATS_MONITOR=1 must NOT enable the debug log (got debug=%v noLog=%v)", debug, noLog)
+	}
+}
+
+// TestMonitorEndpointLoopback boots a real embedded server with
+// UNIBUS_NATS_MONITOR=1 (and DEBUG explicitly off) and proves the monitoring HTTP
+// endpoint answers on loopback only — the exact contract the metrics scraper
+// relies on. The pure decoupling check above already guarantees the log stays out
+// of debug mode for this same env combination.
+func TestMonitorEndpointLoopback(t *testing.T) {
+	t.Setenv("UNIBUS_NATS_DEBUG", "")
+	t.Setenv("UNIBUS_NATS_MONITOR", "1")
+
+	ns, err := StartServer(ServerConfig{
+		StoreDir: t.TempDir(),
+		Host:     "127.0.0.1",
+		Port:     freeLoopbackPort(t),
+	})
+	if err != nil {
+		t.Fatalf("start server with monitoring: %v", err)
+	}
+	defer func() { ns.Shutdown(); ns.WaitForShutdown() }()
+
+	addr := ns.MonitorAddr()
+	if addr == nil {
+		t.Fatal("monitoring endpoint not open with UNIBUS_NATS_MONITOR=1 (MonitorAddr is nil)")
+	}
+	if !addr.IP.IsLoopback() {
+		t.Fatalf("monitoring endpoint bound to %s, must be loopback only", addr.IP)
+	}
+	if addr.Port != 8222 {
+		t.Fatalf("monitoring endpoint on port %d, want the fixed loopback port 8222", addr.Port)
+	}
+
+	// /varz must answer 200 with a non-empty body on loopback.
+	url := "http://" + addr.String() + "/varz"
+	var resp *http.Response
+	deadline := time.Now().Add(3 * time.Second)
+	for time.Now().Before(deadline) {
+		resp, err = http.Get(url) //nolint:gosec // loopback monitoring endpoint, no auth by design
+		if err == nil {
+			break
+		}
+		time.Sleep(50 * time.Millisecond)
+	}
+	if err != nil {
+		t.Fatalf("GET %s: %v", url, err)
+	}
+	defer resp.Body.Close()
+	if resp.StatusCode != http.StatusOK {
+		t.Fatalf("GET %s -> %d, want 200", url, resp.StatusCode)
+	}
+	body, _ := io.ReadAll(resp.Body)
+	if len(body) == 0 {
+		t.Fatalf("GET %s returned an empty body", url)
+	}
+}
+
+// TestMonitorDisabledByDefault proves a server started without either toggle does
+// NOT open the monitoring endpoint, so production stays closed unless opted in.
+func TestMonitorDisabledByDefault(t *testing.T) {
+	t.Setenv("UNIBUS_NATS_DEBUG", "")
+	t.Setenv("UNIBUS_NATS_MONITOR", "")
+
+	ns, err := StartServer(ServerConfig{
+		StoreDir: t.TempDir(),
+		Host:     "127.0.0.1",
+		Port:     freeLoopbackPort(t),
+	})
+	if err != nil {
+		t.Fatalf("start server: %v", err)
+	}
+	defer func() { ns.Shutdown(); ns.WaitForShutdown() }()
+
+	if addr := ns.MonitorAddr(); addr != nil {
+		t.Fatalf("monitoring endpoint open (%s) without UNIBUS_NATS_MONITOR — must stay closed by default", addr)
+	}
+}
+
+func freeLoopbackPort(t *testing.T) int {
+	t.Helper()
+	l, err := net.Listen("tcp", "127.0.0.1:0")
+	if err != nil {
+		t.Fatalf("free port: %v", err)
+	}
+	defer l.Close()
+	return l.Addr().(*net.TCPAddr).Port
+}

pkg/membership/invites.go

@@ -0,0 +1,296 @@
+package membership
+
+import (
+	"crypto/rand"
+	"database/sql"
+	"encoding/hex"
+	"errors"
+	"fmt"
+	"strings"
+	"time"
+)
+
+// Invite is a single-use registration token the admin mints so a brand-new
+// identity can join the bus allowlist WITHOUT the admin ever handling its
+// private key (the wallet model: the key is born and stays on the user's
+// device; only the public key is published, via POST /register).
+//
+// The admin fixes the handle and role at mint time; the registering client may
+// NOT change them (no privilege escalation). Token is 32 random bytes in
+// lowercase hex (64 chars). ExpiresAt and CreatedAt are RFC3339Nano UTC. Used
+// flips to true the instant the invite is consumed, and an invite can be
+// consumed at most once. The audit fields (UsedAt/UsedSignPub/UsedKexPub) are
+// empty until the invite is consumed; they record which keys claimed it, so the
+// link between an invite and the identity it created stays traceable even though
+// the allowlist row itself stores only the signing key.
+type Invite struct {
+	Token     string `json:"token"`
+	Handle    string `json:"handle"`
+	Role      string `json:"role"`
+	ExpiresAt string `json:"expires_at"`
+	Used      bool   `json:"used"`
+	CreatedAt string `json:"created_at"`
+
+	// Audit (populated on consume; omitted on the wire while pending).
+	UsedAt      string `json:"used_at,omitempty"`
+	UsedSignPub string `json:"used_sign_pub,omitempty"`
+	UsedKexPub  string `json:"used_kex_pub,omitempty"`
+}
+
+// Invite-flow sentinels. They let callers (and the HTTP layer) map a failed
+// consume to a precise status code without string-matching: an unknown token is
+// ErrNotFound (reused from the store), a spent token is ErrInviteUsed, a
+// past-deadline token is ErrInviteExpired. ErrUserExists (from users.go) is
+// reused when the presented signing key is already registered.
+var (
+	ErrInviteUsed    = errors.New("membership: invite already used")
+	ErrInviteExpired = errors.New("membership: invite expired")
+)
+
+// defaultInviteTTL is the lifetime of an invite when the caller passes a
+// non-positive ttlSecs. Seven days mirrors a typical "share this link this
+// week" expectation while keeping the un-authenticated /register window bounded.
+const defaultInviteTTL = 7 * 24 * time.Hour
+
+// newInviteToken returns 32 cryptographically-random bytes as lowercase hex (64
+// chars). The token IS the bearer secret that authorizes /register, so it must
+// be unguessable; crypto/rand is the only acceptable source.
+func newInviteToken() (string, error) {
+	b := make([]byte, 32)
+	if _, err := rand.Read(b); err != nil {
+		return "", fmt.Errorf("membership: generate invite token: %w", err)
+	}
+	return hex.EncodeToString(b), nil
+}
+
+// inviteTTL resolves a caller-supplied ttlSecs into a concrete duration,
+// defaulting to defaultInviteTTL when non-positive.
+func inviteTTL(ttlSecs int) time.Duration {
+	if ttlSecs <= 0 {
+		return defaultInviteTTL
+	}
+	return time.Duration(ttlSecs) * time.Second
+}
+
+// inviteIsExpired reports whether the RFC3339 expiry has passed. A token whose
+// expiry cannot be parsed is treated as expired (fail closed): a corrupt
+// deadline must never widen the unauthenticated registration window.
+func inviteIsExpired(expiresAt string) bool {
+	exp, err := time.Parse(time.RFC3339Nano, expiresAt)
+	if err != nil {
+		return true
+	}
+	return time.Now().UTC().After(exp)
+}
+
+// validateInviteRole normalizes and validates the role an invite may carry. It
+// mirrors AddUser: empty defaults to member, and only admin|member are allowed
+// (an admin minting an admin invite is deliberate and permitted).
+func validateInviteRole(role string) (string, error) {
+	if role == "" {
+		return RoleMember, nil
+	}
+	if role != RoleAdmin && role != RoleMember {
+		return "", fmt.Errorf("membership: invalid role %q (want %q or %q)", role, RoleAdmin, RoleMember)
+	}
+	return role, nil
+}
+
+// ---- SQLite implementation ------------------------------------------------
+
+// CreateInvite mints a single-use invite for a future user. handle is required;
+// role defaults to member and must be admin|member. ttlSecs sets the lifetime
+// (non-positive uses the 7-day default). The token is 32 random bytes in hex.
+func (s *sqliteStore) CreateInvite(handle, role string, ttlSecs int) (Invite, error) {
+	if handle == "" {
+		return Invite{}, fmt.Errorf("membership: CreateInvite: handle required")
+	}
+	role, err := validateInviteRole(role)
+	if err != nil {
+		return Invite{}, err
+	}
+	token, err := newInviteToken()
+	if err != nil {
+		return Invite{}, err
+	}
+	now := time.Now().UTC()
+	inv := Invite{
+		Token:     token,
+		Handle:    handle,
+		Role:      role,
+		ExpiresAt: now.Add(inviteTTL(ttlSecs)).Format(time.RFC3339Nano),
+		Used:      false,
+		CreatedAt: now.Format(time.RFC3339Nano),
+	}
+	if _, err := s.db.Exec(
+		`INSERT INTO invites (token, handle, role, expires_at, used, created_at) VALUES (?, ?, ?, ?, 0, ?)`,
+		inv.Token, inv.Handle, inv.Role, inv.ExpiresAt, inv.CreatedAt,
+	); err != nil {
+		return Invite{}, fmt.Errorf("membership: insert invite: %w", err)
+	}
+	return inv, nil
+}
+
+// GetInvite returns the invite with the given token, or ErrNotFound (wrapped)
+// when there is none.
+func (s *sqliteStore) GetInvite(token string) (Invite, error) {
+	var inv Invite
+	var used int
+	var usedAt, usedSign, usedKex sql.NullString
+	err := s.db.QueryRow(
+		`SELECT token, handle, role, expires_at, used, created_at, used_at, used_sign_pub, used_kex_pub
+		 FROM invites WHERE token = ?`, token,
+	).Scan(&inv.Token, &inv.Handle, &inv.Role, &inv.ExpiresAt, &used, &inv.CreatedAt, &usedAt, &usedSign, &usedKex)
+	if err != nil {
+		if errors.Is(err, sql.ErrNoRows) {
+			return Invite{}, fmt.Errorf("membership: get invite %q: %w", token, ErrNotFound)
+		}
+		return Invite{}, fmt.Errorf("membership: get invite %q: %w", token, err)
+	}
+	inv.Used = used != 0
+	inv.UsedAt, inv.UsedSignPub, inv.UsedKexPub = usedAt.String, usedSign.String, usedKex.String
+	return inv, nil
+}
+
+// ListInvites returns every invite ordered newest-first (by created_at). It
+// includes consumed invites so the admin panel can show the full picture; the
+// caller filters to "pending" when it wants only live links.
+func (s *sqliteStore) ListInvites() ([]Invite, error) {
+	rows, err := s.db.Query(
+		`SELECT token, handle, role, expires_at, used, created_at, used_at, used_sign_pub, used_kex_pub
+		 FROM invites ORDER BY created_at DESC, token`,
+	)
+	if err != nil {
+		return nil, fmt.Errorf("membership: list invites: %w", err)
+	}
+	defer rows.Close()
+
+	var out []Invite
+	for rows.Next() {
+		var inv Invite
+		var used int
+		var usedAt, usedSign, usedKex sql.NullString
+		if err := rows.Scan(&inv.Token, &inv.Handle, &inv.Role, &inv.ExpiresAt, &used, &inv.CreatedAt, &usedAt, &usedSign, &usedKex); err != nil {
+			return nil, fmt.Errorf("membership: scan invite: %w", err)
+		}
+		inv.Used = used != 0
+		inv.UsedAt, inv.UsedSignPub, inv.UsedKexPub = usedAt.String, usedSign.String, usedKex.String
+		out = append(out, inv)
+	}
+	return out, rows.Err()
+}
+
+// ConsumeInvite atomically validates and spends an invite, registering the
+// presented signing key as a bus user with the invite's handle and role. It is
+// the ONLY path that adds to the allowlist without an admin signature: the
+// bearer token is the authorization, so the checks here are the security
+// boundary.
+//
+// Atomicity (single transaction): the invite is marked used FIRST (guarded by
+// `used = 0`, so two concurrent consumers cannot both win), then the user is
+// inserted. A token that passes validation is therefore spent exactly once.
+// Special case: if the signing key is already registered, the user INSERT hits
+// the PRIMARY KEY and we return ErrUserExists — but the invite stays SPENT (we
+// commit the mark), matching the JetStream backend's burn-on-claim semantics so
+// the two stores behave identically. A genuine backend error rolls everything
+// back, leaving the invite reusable.
+func (s *sqliteStore) ConsumeInvite(token, signPub, kexPub string) error {
+	signPub = normalizeSignPub(signPub)
+	kexPub = normalizeSignPub(kexPub)
+	if signPub == "" {
+		return fmt.Errorf("membership: ConsumeInvite: sign_pub required")
+	}
+
+	tx, err := s.db.Begin()
+	if err != nil {
+		return fmt.Errorf("membership: ConsumeInvite: begin: %w", err)
+	}
+	defer tx.Rollback()
+
+	var handle, role, expiresAt string
+	var used int
+	err = tx.QueryRow(
+		`SELECT handle, role, expires_at, used FROM invites WHERE token = ?`, token,
+	).Scan(&handle, &role, &expiresAt, &used)
+	if err != nil {
+		if errors.Is(err, sql.ErrNoRows) {
+			return fmt.Errorf("membership: consume invite %q: %w", token, ErrNotFound)
+		}
+		return fmt.Errorf("membership: consume invite %q: %w", token, err)
+	}
+	if used != 0 {
+		return fmt.Errorf("membership: consume invite %q: %w", token, ErrInviteUsed)
+	}
+	if inviteIsExpired(expiresAt) {
+		return fmt.Errorf("membership: consume invite %q: %w", token, ErrInviteExpired)
+	}
+
+	// Mark used first, guarded by used = 0 so a concurrent consumer that already
+	// flipped it (rows affected = 0) is rejected as used rather than double-spending.
+	now := nowRFC3339()
+	res, err := tx.Exec(
+		`UPDATE invites SET used = 1, used_at = ?, used_sign_pub = ?, used_kex_pub = ? WHERE token = ? AND used = 0`,
+		now, signPub, kexPub, token,
+	)
+	if err != nil {
+		return fmt.Errorf("membership: consume invite %q: mark used: %w", token, err)
+	}
+	n, err := res.RowsAffected()
+	if err != nil {
+		return fmt.Errorf("membership: consume invite %q: rows affected: %w", token, err)
+	}
+	if n == 0 {
+		return fmt.Errorf("membership: consume invite %q: %w", token, ErrInviteUsed)
+	}
+
+	// Register the user with the invite-fixed handle and role.
+	_, err = tx.Exec(
+		`INSERT INTO users (sign_pub, handle, role, status, created_at) VALUES (?, ?, ?, ?, ?)`,
+		signPub, handle, role, StatusActive, now,
+	)
+	if err != nil {
+		// Already-registered key: the invite is still spent (commit the mark) so
+		// the burn-on-claim contract matches the KV store. Any other failure rolls back.
+		if isUniqueViolation(err) {
+			if cErr := tx.Commit(); cErr != nil {
+				return fmt.Errorf("membership: consume invite %q: commit: %w", token, cErr)
+			}
+			return ErrUserExists
+		}
+		return fmt.Errorf("membership: consume invite %q: insert user: %w", token, err)
+	}
+	if err := tx.Commit(); err != nil {
+		return fmt.Errorf("membership: consume invite %q: commit: %w", token, err)
+	}
+	return nil
+}
+
+// CancelInvite removes a pending invite (the admin revoked the link before it
+// was used). It hard-deletes the row; a consumed invite stays for audit only if
+// the caller targets a pending token. Deleting an unknown token returns
+// ErrNotFound so the HTTP layer can answer 404.
+func (s *sqliteStore) CancelInvite(token string) error {
+	res, err := s.db.Exec(`DELETE FROM invites WHERE token = ?`, token)
+	if err != nil {
+		return fmt.Errorf("membership: cancel invite %q: %w", token, err)
+	}
+	n, err := res.RowsAffected()
+	if err != nil {
+		return fmt.Errorf("membership: cancel invite %q: rows affected: %w", token, err)
+	}
+	if n == 0 {
+		return fmt.Errorf("membership: cancel invite %q: %w", token, ErrNotFound)
+	}
+	return nil
+}
+
+// isUniqueViolation reports whether err is a SQLite UNIQUE/PRIMARY KEY conflict.
+// modernc.org/sqlite surfaces it as a message fragment; matching it here keeps
+// the string-matching in one place (the same fragments AddUser checks inline).
+func isUniqueViolation(err error) bool {
+	if err == nil {
+		return false
+	}
+	msg := err.Error()
+	return strings.Contains(msg, "UNIQUE constraint") || strings.Contains(msg, "PRIMARY KEY")
+}

pkg/membership/invites_http_test.go

@@ -0,0 +1,194 @@
+package membership
+
+import (
+	"bytes"
+	"encoding/hex"
+	"encoding/json"
+	"io"
+	"net/http"
+	"testing"
+	"time"
+
+	cs "fn-registry/functions/cybersecurity"
+)
+
+// postRegister posts an UNSIGNED /register request (the wallet-model join: the
+// new identity is not yet in the allowlist, so it cannot sign). It returns the
+// status and body so a test can assert the precise code.
+func postRegister(t *testing.T, h *authHarness, body registerReq) (int, string) {
+	t.Helper()
+	b, err := json.Marshal(body)
+	if err != nil {
+		t.Fatalf("marshal register: %v", err)
+	}
+	resp, err := http.Post(h.ts.URL+"/register", "application/json", bytes.NewReader(b))
+	if err != nil {
+		t.Fatalf("post register: %v", err)
+	}
+	defer resp.Body.Close()
+	rb, _ := io.ReadAll(resp.Body)
+	return resp.StatusCode, string(rb)
+}
+
+// TestInvitesHTTP_Golden is the end-to-end wallet-model flow over real HTTP:
+// alice (admin) mints an invite, a brand-new identity redeems it UNSIGNED via
+// /register, the user then appears in the admin allowlist, and a second redeem of
+// the same token is rejected as used.
+func TestInvitesHTTP_Golden(t *testing.T) {
+	h := newAuthHarness(t, AuthEnforce)
+
+	// Admin mints an invite.
+	var inv createInviteResp
+	code, body := signedJSON(t, h, "POST", "/invites",
+		createInviteReq{Handle: "newbie", Role: RoleMember}, h.alice, 1)
+	if code != http.StatusCreated {
+		t.Fatalf("admin create invite should be 201, got %d (%s)", code, body)
+	}
+	if err := json.Unmarshal([]byte(body), &inv); err != nil {
+		t.Fatalf("decode invite: %v (%s)", err, body)
+	}
+	if len(inv.Token) != 64 || inv.ExpiresAt == "" {
+		t.Fatalf("invite token/expiry malformed: %+v", inv)
+	}
+
+	// A brand-new identity redeems it WITHOUT any admin signature.
+	id, _ := cs.GenerateIdentity()
+	signPub := hex.EncodeToString(id.SignPub)
+	kexPub := hex.EncodeToString(id.KexPub)
+	if code, body := postRegister(t, h, registerReq{Token: inv.Token, SignPub: signPub, KexPub: kexPub}); code != http.StatusCreated {
+		t.Fatalf("register should be 201, got %d (%s)", code, body)
+	}
+
+	// The user now appears in the admin allowlist with the invite's handle/role.
+	users := listUsers(t, h, 2)
+	row, ok := findUser(users, signPub)
+	if !ok {
+		t.Fatalf("registered user missing from allowlist: %+v", users)
+	}
+	if row.Handle != "newbie" || row.Role != RoleMember || row.Status != StatusActive {
+		t.Fatalf("registered user row wrong: %+v", row)
+	}
+
+	// The invite is no longer pending.
+	if code, body := signedJSON(t, h, "GET", "/invites", nil, h.alice, 3); code == http.StatusOK {
+		var pend []inviteJSON
+		_ = json.Unmarshal([]byte(body), &pend)
+		for _, p := range pend {
+			if p.Token == inv.Token {
+				t.Fatalf("consumed invite should not be listed as pending: %+v", pend)
+			}
+		}
+	}
+
+	// Single-use: a second redeem of the same token is 409 used.
+	id2, _ := cs.GenerateIdentity()
+	if code, body := postRegister(t, h, registerReq{
+		Token: inv.Token, SignPub: hex.EncodeToString(id2.SignPub), KexPub: hex.EncodeToString(id2.KexPub),
+	}); code != http.StatusConflict {
+		t.Fatalf("second redeem should be 409, got %d (%s)", code, body)
+	}
+}
+
+// TestInvitesHTTP_RegisterValidation covers /register input + state errors: an
+// unknown token is 404, an expired token is 410, and malformed hex keys are 400 —
+// each WITHOUT registering anything.
+func TestInvitesHTTP_RegisterValidation(t *testing.T) {
+	h := newAuthHarness(t, AuthEnforce)
+	id, _ := cs.GenerateIdentity()
+	signPub := hex.EncodeToString(id.SignPub)
+	kexPub := hex.EncodeToString(id.KexPub)
+
+	// Unknown token -> 404.
+	if code, body := postRegister(t, h, registerReq{Token: "deadbeef", SignPub: signPub, KexPub: kexPub}); code != http.StatusNotFound {
+		t.Fatalf("unknown token should be 404, got %d (%s)", code, body)
+	}
+
+	// Malformed sign_pub -> 400.
+	if code, body := postRegister(t, h, registerReq{Token: "x", SignPub: "abcd", KexPub: kexPub}); code != http.StatusBadRequest {
+		t.Fatalf("malformed sign_pub should be 400, got %d (%s)", code, body)
+	}
+
+	// Malformed kex_pub -> 400.
+	if code, body := postRegister(t, h, registerReq{Token: "x", SignPub: signPub, KexPub: "zzzz"}); code != http.StatusBadRequest {
+		t.Fatalf("malformed kex_pub should be 400, got %d (%s)", code, body)
+	}
+
+	// Expired token -> 410. Mint via the admin API, then force its deadline past
+	// directly in the store (white-box).
+	var inv createInviteResp
+	_, body := signedJSON(t, h, "POST", "/invites", createInviteReq{Handle: "late", Role: RoleMember}, h.alice, 1)
+	if err := json.Unmarshal([]byte(body), &inv); err != nil {
+		t.Fatalf("decode invite: %v (%s)", err, body)
+	}
+	ss, ok := h.store.(*sqliteStore)
+	if !ok {
+		t.Fatalf("expected sqliteStore harness")
+	}
+	past := time.Now().Add(-time.Hour).UTC().Format(time.RFC3339Nano)
+	if _, err := ss.db.Exec(`UPDATE invites SET expires_at = ? WHERE token = ?`, past, inv.Token); err != nil {
+		t.Fatalf("force expire: %v", err)
+	}
+	if code, rb := postRegister(t, h, registerReq{Token: inv.Token, SignPub: signPub, KexPub: kexPub}); code != http.StatusGone {
+		t.Fatalf("expired token should be 410, got %d (%s)", code, rb)
+	}
+}
+
+// TestInvitesHTTP_NonAdminForbidden is the security spine for the new endpoints:
+// a REGISTERED non-admin (bob) is denied on POST /invites, GET /invites,
+// DELETE /invites/{token}, and DELETE /users/{signpub} — each a 403 by role.
+func TestInvitesHTTP_NonAdminForbidden(t *testing.T) {
+	h := newAuthHarness(t, AuthEnforce)
+
+	bob, _ := cs.GenerateIdentity()
+	register(t, h, bob, "bob") // role member
+	bobPub := hex.EncodeToString(bob.SignPub)
+
+	checks := []struct {
+		name   string
+		method string
+		path   string
+		body   any
+	}{
+		{"create invite", "POST", "/invites", createInviteReq{Handle: "x", Role: RoleMember}},
+		{"list invites", "GET", "/invites", nil},
+		{"cancel invite", "DELETE", "/invites/sometoken", nil},
+		{"delete user", "DELETE", "/users/" + bobPub, nil},
+	}
+	for i, c := range checks {
+		code, body := signedJSON(t, h, c.method, c.path, c.body, bob, i+1)
+		if code != http.StatusForbidden {
+			t.Fatalf("non-admin %s should be 403, got %d (%s)", c.name, code, body)
+		}
+	}
+}
+
+// TestUsersHTTP_HardDelete proves DELETE /users/{signpub} purges a user (distinct
+// from revoke's status flip): alice adds carol, hard-deletes her, and carol then
+// vanishes from the allowlist entirely (not merely flagged revoked).
+func TestUsersHTTP_HardDelete(t *testing.T) {
+	h := newAuthHarness(t, AuthEnforce)
+
+	carol, _ := cs.GenerateIdentity()
+	carolPub := hex.EncodeToString(carol.SignPub)
+	if code, body := signedJSON(t, h, "POST", "/users",
+		addUserReq{SignPub: carolPub, Handle: "carol", Role: RoleMember}, h.alice, 1); code != http.StatusCreated {
+		t.Fatalf("add carol should be 201, got %d (%s)", code, body)
+	}
+
+	// Hard-delete carol.
+	if code, body := signedJSON(t, h, "DELETE", "/users/"+carolPub, nil, h.alice, 2); code != http.StatusOK {
+		t.Fatalf("hard-delete carol should be 200, got %d (%s)", code, body)
+	}
+
+	// She is gone entirely — not present in the list at all (vs revoke, which
+	// keeps her as status=revoked).
+	users := listUsers(t, h, 3)
+	if _, ok := findUser(users, carolPub); ok {
+		t.Fatalf("hard-deleted carol must NOT appear in the allowlist: %+v", users)
+	}
+
+	// Deleting her again is a 404.
+	if code, body := signedJSON(t, h, "DELETE", "/users/"+carolPub, nil, h.alice, 4); code != http.StatusNotFound {
+		t.Fatalf("re-delete should be 404, got %d (%s)", code, body)
+	}
+}

pkg/membership/invites_test.go

@@ -0,0 +1,186 @@
+package membership
+
+import (
+	"encoding/hex"
+	"encoding/json"
+	"errors"
+	"testing"
+	"time"
+
+	cs "fn-registry/functions/cybersecurity"
+)
+
+// newIDHex generates a fresh identity and returns its signing and key-exchange
+// public keys as lowercase hex — the two keys a client presents to /register.
+func newIDHex(t *testing.T) (signPub, kexPub string) {
+	t.Helper()
+	id, err := cs.GenerateIdentity()
+	if err != nil {
+		t.Fatalf("identity: %v", err)
+	}
+	return hex.EncodeToString(id.SignPub), hex.EncodeToString(id.KexPub)
+}
+
+// inviteSuite drives the full invite lifecycle against any Store backend: mint,
+// look up, redeem (which registers the user), reject a second redeem (single-use)
+// and a non-existent token, reject an expired token (forced past via the
+// backend-specific forceExpire closure), and hard-delete a user. It is shared by
+// the SQLite and JetStream tests so both backends prove identical behavior.
+func inviteSuite(t *testing.T, s Store, forceExpire func(token string)) {
+	t.Helper()
+
+	// Mint an invite fixing handle + role.
+	inv, err := s.CreateInvite("alice-new", RoleMember, 3600)
+	if err != nil {
+		t.Fatalf("CreateInvite: %v", err)
+	}
+	if len(inv.Token) != 64 {
+		t.Fatalf("token should be 64 hex chars, got %d (%q)", len(inv.Token), inv.Token)
+	}
+	if inv.Used {
+		t.Fatalf("fresh invite must not be used")
+	}
+
+	// GetInvite round-trips it.
+	got, err := s.GetInvite(inv.Token)
+	if err != nil || got.Handle != "alice-new" || got.Role != RoleMember {
+		t.Fatalf("GetInvite mismatch: %+v err=%v", got, err)
+	}
+
+	// Redeem it: the presented signing key joins the allowlist with the invite's
+	// handle and role.
+	signPub, kexPub := newIDHex(t)
+	if err := s.ConsumeInvite(inv.Token, signPub, kexPub); err != nil {
+		t.Fatalf("ConsumeInvite (golden): %v", err)
+	}
+	u, err := s.GetUser(signPub)
+	if err != nil {
+		t.Fatalf("GetUser after register: %v", err)
+	}
+	if u.Handle != "alice-new" || u.Role != RoleMember || u.Status != StatusActive {
+		t.Fatalf("registered user wrong: %+v", u)
+	}
+	if !s.IsAuthorized(signPub) {
+		t.Fatalf("registered user should be authorized")
+	}
+
+	// Single-use: redeeming the same token again (even with a different identity)
+	// is rejected as used.
+	sp2, kp2 := newIDHex(t)
+	if err := s.ConsumeInvite(inv.Token, sp2, kp2); !errors.Is(err, ErrInviteUsed) {
+		t.Fatalf("second redeem should be ErrInviteUsed, got %v", err)
+	}
+	if _, err := s.GetUser(sp2); !errors.Is(err, ErrNotFound) {
+		t.Fatalf("second identity must NOT be registered, got %v", err)
+	}
+
+	// Unknown token is ErrNotFound.
+	if err := s.ConsumeInvite("deadbeef", "ab", "cd"); !errors.Is(err, ErrNotFound) {
+		t.Fatalf("unknown token should be ErrNotFound, got %v", err)
+	}
+
+	// Expired invite: mint one, force its deadline into the past, redeem -> rejected.
+	exp, err := s.CreateInvite("late", RoleMember, 3600)
+	if err != nil {
+		t.Fatalf("CreateInvite expired: %v", err)
+	}
+	forceExpire(exp.Token)
+	sp3, kp3 := newIDHex(t)
+	if err := s.ConsumeInvite(exp.Token, sp3, kp3); !errors.Is(err, ErrInviteExpired) {
+		t.Fatalf("expired redeem should be ErrInviteExpired, got %v", err)
+	}
+
+	// CancelInvite removes a pending invite; redeeming it afterward is ErrNotFound.
+	canc, err := s.CreateInvite("cancelme", RoleMember, 3600)
+	if err != nil {
+		t.Fatalf("CreateInvite cancel: %v", err)
+	}
+	if err := s.CancelInvite(canc.Token); err != nil {
+		t.Fatalf("CancelInvite: %v", err)
+	}
+	if err := s.ConsumeInvite(canc.Token, sp3, kp3); !errors.Is(err, ErrNotFound) {
+		t.Fatalf("cancelled invite redeem should be ErrNotFound, got %v", err)
+	}
+
+	// Hard-delete the registered user: it disappears from the allowlist entirely.
+	if err := s.DeleteUser(signPub); err != nil {
+		t.Fatalf("DeleteUser: %v", err)
+	}
+	if _, err := s.GetUser(signPub); !errors.Is(err, ErrNotFound) {
+		t.Fatalf("deleted user should be ErrNotFound, got %v", err)
+	}
+	if s.IsAuthorized(signPub) {
+		t.Fatalf("deleted user must not be authorized")
+	}
+	// Deleting an unknown key is ErrNotFound.
+	if err := s.DeleteUser(signPub); !errors.Is(err, ErrNotFound) {
+		t.Fatalf("re-delete should be ErrNotFound, got %v", err)
+	}
+}
+
+// TestInvitesSQLite runs the suite against the default SQLite backend, forcing
+// expiry with a direct UPDATE on the embedded DB (white-box, same package).
+func TestInvitesSQLite(t *testing.T) {
+	s := openTestStore(t)
+	inviteSuite(t, s, func(token string) {
+		past := time.Now().Add(-time.Hour).UTC().Format(time.RFC3339Nano)
+		if _, err := s.db.Exec(`UPDATE invites SET expires_at = ? WHERE token = ?`, past, token); err != nil {
+			t.Fatalf("force expire: %v", err)
+		}
+	})
+}
+
+// TestInvitesJetStream runs the same suite against the replicated KV backend,
+// forcing expiry by re-Putting the invite JSON with a past deadline.
+func TestInvitesJetStream(t *testing.T) {
+	s, _, _ := newKVStore(t)
+	inviteSuite(t, s, func(token string) {
+		inv, err := s.GetInvite(token)
+		if err != nil {
+			t.Fatalf("force expire: get invite: %v", err)
+		}
+		inv.ExpiresAt = time.Now().Add(-time.Hour).UTC().Format(time.RFC3339Nano)
+		b, err := json.Marshal(inv)
+		if err != nil {
+			t.Fatalf("force expire: marshal: %v", err)
+		}
+		ctx, cancel := s.ctx()
+		defer cancel()
+		if _, err := s.invites.Put(ctx, token, b); err != nil {
+			t.Fatalf("force expire: put: %v", err)
+		}
+	})
+}
+
+// TestConsumeInvite_AlreadyRegistered covers the burn-on-claim edge: redeeming a
+// valid invite with a signing key that is already registered surfaces
+// ErrUserExists AND spends the invite (both backends behave identically).
+func TestConsumeInvite_AlreadyRegistered(t *testing.T) {
+	for _, tc := range []struct {
+		name string
+		open func(t *testing.T) Store
+	}{
+		{"sqlite", func(t *testing.T) Store { return openTestStore(t) }},
+		{"jetstream", func(t *testing.T) Store { s, _, _ := newKVStore(t); return s }},
+	} {
+		t.Run(tc.name, func(t *testing.T) {
+			s := tc.open(t)
+			signPub, kexPub := newIDHex(t)
+			if err := s.AddUser(signPub, "existing", RoleMember); err != nil {
+				t.Fatalf("seed user: %v", err)
+			}
+			inv, err := s.CreateInvite("dup", RoleMember, 3600)
+			if err != nil {
+				t.Fatalf("CreateInvite: %v", err)
+			}
+			if err := s.ConsumeInvite(inv.Token, signPub, kexPub); !errors.Is(err, ErrUserExists) {
+				t.Fatalf("redeem with registered key should be ErrUserExists, got %v", err)
+			}
+			// The invite is spent (burn-on-claim): a fresh identity cannot reuse it.
+			sp2, kp2 := newIDHex(t)
+			if err := s.ConsumeInvite(inv.Token, sp2, kp2); !errors.Is(err, ErrInviteUsed) {
+				t.Fatalf("invite should be spent after a burned claim, got %v", err)
+			}
+		})
+	}
+}

pkg/membership/jetstream_store.go

@@ -50,6 +50,7 @@ const (
 	bucketByMember  = "UNIBUS_rooms_by_member"
 	bucketRoomKeys  = "UNIBUS_room_keys"
 	bucketUsers     = "UNIBUS_users"
+	bucketInvites   = "UNIBUS_invites"
 	defaultKVOpTime = 5 * time.Second
 )
 
@@ -71,6 +72,7 @@ type jetstreamStore struct {
 	byMember  jetstream.KeyValue
 	keys      jetstream.KeyValue
 	users     jetstream.KeyValue
+	invites   jetstream.KeyValue
 	opTimeout time.Duration
 }
 
@@ -108,6 +110,7 @@ func OpenJetStream(js jetstream.JetStream, cfg JetStreamConfig) (Store, error) {
 		{bucketByMember, &s.byMember},
 		{bucketRoomKeys, &s.keys},
 		{bucketUsers, &s.users},
+		{bucketInvites, &s.invites},
 	} {
 		var kv jetstream.KeyValue
 		var lastErr error
@@ -498,6 +501,28 @@ func (s *jetstreamStore) RevokeUser(signPub string) error {
 	return nil
 }
 
+// DeleteUser hard-deletes a user from the KV allowlist (the purge counterpart of
+// RevokeUser's status flip). It checks existence first so deleting an unknown key
+// is ErrNotFound (KV Delete is otherwise idempotent and would not signal a miss).
+// Only the allowlist key is removed; room memberships the ex-user holds become
+// inert because they can no longer authenticate — see the SQLite DeleteUser for
+// the full rationale on why room state is left untouched.
+func (s *jetstreamStore) DeleteUser(signPub string) error {
+	signPub = normalizeSignPub(signPub)
+	ctx, cancel := s.ctx()
+	defer cancel()
+	if _, err := s.users.Get(ctx, signPub); err != nil {
+		if errors.Is(err, jetstream.ErrKeyNotFound) {
+			return fmt.Errorf("membership: delete user %q: %w", signPub, ErrNotFound)
+		}
+		return fmt.Errorf("membership: delete user %q: %w", signPub, err)
+	}
+	if err := s.users.Delete(ctx, signPub); err != nil {
+		return fmt.Errorf("membership: delete user %q: %w", signPub, err)
+	}
+	return nil
+}
+
 // IsAuthorized reports whether signPub is an active bus user. Any backend error
 // (including a KV quorum loss or timeout) yields false: fail closed.
 func (s *jetstreamStore) IsAuthorized(signPub string) bool {
@@ -533,6 +558,173 @@ func (s *jetstreamStore) HasAdmin() bool {
 	return false
 }
 
+// ---- invites (single-use registration tokens) ----------------------------
+
+func (s *jetstreamStore) CreateInvite(handle, role string, ttlSecs int) (Invite, error) {
+	if handle == "" {
+		return Invite{}, fmt.Errorf("membership: CreateInvite: handle required")
+	}
+	role, err := validateInviteRole(role)
+	if err != nil {
+		return Invite{}, err
+	}
+	token, err := newInviteToken()
+	if err != nil {
+		return Invite{}, err
+	}
+	now := time.Now().UTC()
+	inv := Invite{
+		Token:     token,
+		Handle:    handle,
+		Role:      role,
+		ExpiresAt: now.Add(inviteTTL(ttlSecs)).Format(time.RFC3339Nano),
+		Used:      false,
+		CreatedAt: now.Format(time.RFC3339Nano),
+	}
+	b, err := json.Marshal(inv)
+	if err != nil {
+		return Invite{}, fmt.Errorf("membership: marshal invite: %w", err)
+	}
+	ctx, cancel := s.ctx()
+	defer cancel()
+	// Create (not Put) so a token collision is rejected rather than silently
+	// overwriting a live invite — a 32-byte random collision is astronomically
+	// unlikely, but Create makes the single-use guarantee unconditional.
+	if _, err := s.invites.Create(ctx, token, b); err != nil {
+		if errors.Is(err, jetstream.ErrKeyExists) {
+			return Invite{}, fmt.Errorf("membership: create invite: token collision")
+		}
+		return Invite{}, fmt.Errorf("membership: create invite: %w", err)
+	}
+	return inv, nil
+}
+
+func (s *jetstreamStore) GetInvite(token string) (Invite, error) {
+	ctx, cancel := s.ctx()
+	defer cancel()
+	e, err := s.invites.Get(ctx, token)
+	if err != nil {
+		if errors.Is(err, jetstream.ErrKeyNotFound) {
+			return Invite{}, fmt.Errorf("membership: get invite %q: %w", token, ErrNotFound)
+		}
+		return Invite{}, fmt.Errorf("membership: get invite %q: %w", token, err)
+	}
+	var inv Invite
+	if err := json.Unmarshal(e.Value(), &inv); err != nil {
+		return Invite{}, fmt.Errorf("membership: unmarshal invite: %w", err)
+	}
+	return inv, nil
+}
+
+func (s *jetstreamStore) ListInvites() ([]Invite, error) {
+	ctx, cancel := s.ctx()
+	w, err := s.invites.WatchAll(ctx, jetstream.IgnoreDeletes())
+	if err != nil {
+		cancel()
+		return nil, fmt.Errorf("membership: list invites: %w", err)
+	}
+	defer cancel()
+	defer w.Stop()
+	var out []Invite
+	for {
+		select {
+		case e := <-w.Updates():
+			if e == nil {
+				sort.Slice(out, func(i, j int) bool {
+					if out[i].CreatedAt != out[j].CreatedAt {
+						return out[i].CreatedAt > out[j].CreatedAt // newest first
+					}
+					return out[i].Token < out[j].Token
+				})
+				return out, nil
+			}
+			var inv Invite
+			if err := json.Unmarshal(e.Value(), &inv); err != nil {
+				return nil, fmt.Errorf("membership: unmarshal invite: %w", err)
+			}
+			out = append(out, inv)
+		case <-ctx.Done():
+			return nil, ctx.Err()
+		}
+	}
+}
+
+// ConsumeInvite spends a KV invite and registers the presented signing key. With
+// no multi-key transaction, single-use is enforced by a compare-and-swap on the
+// invite: the token is marked used via Update against the revision read by Get,
+// so only ONE concurrent consumer can win the swap; the loser sees a revision
+// mismatch and is rejected as used. The user is registered AFTER the successful
+// swap. Burn-on-claim: if the signing key is already registered the swap has
+// already spent the token and we surface ErrUserExists — the SQLite store commits
+// the same way, so both backends behave identically.
+func (s *jetstreamStore) ConsumeInvite(token, signPub, kexPub string) error {
+	signPub = normalizeSignPub(signPub)
+	kexPub = normalizeSignPub(kexPub)
+	if signPub == "" {
+		return fmt.Errorf("membership: ConsumeInvite: sign_pub required")
+	}
+
+	ctx, cancel := s.ctx()
+	defer cancel()
+	e, err := s.invites.Get(ctx, token)
+	if err != nil {
+		if errors.Is(err, jetstream.ErrKeyNotFound) {
+			return fmt.Errorf("membership: consume invite %q: %w", token, ErrNotFound)
+		}
+		return fmt.Errorf("membership: consume invite %q: %w", token, err)
+	}
+	var inv Invite
+	if err := json.Unmarshal(e.Value(), &inv); err != nil {
+		return fmt.Errorf("membership: unmarshal invite: %w", err)
+	}
+	if inv.Used {
+		return fmt.Errorf("membership: consume invite %q: %w", token, ErrInviteUsed)
+	}
+	if inviteIsExpired(inv.ExpiresAt) {
+		return fmt.Errorf("membership: consume invite %q: %w", token, ErrInviteExpired)
+	}
+
+	inv.Used = true
+	inv.UsedAt = nowRFC3339()
+	inv.UsedSignPub = signPub
+	inv.UsedKexPub = kexPub
+	b, err := json.Marshal(inv)
+	if err != nil {
+		return fmt.Errorf("membership: marshal invite: %w", err)
+	}
+	// CAS: Update only succeeds if the invite is still at the revision we read, so
+	// a racing consumer that already flipped it loses here. A failed swap is
+	// conservatively treated as "already used" (the common cause); the caller can
+	// re-read to learn the precise state.
+	if _, err := s.invites.Update(ctx, token, b, e.Revision()); err != nil {
+		return fmt.Errorf("membership: consume invite %q: %w", token, ErrInviteUsed)
+	}
+
+	// Token is now spent. Register the user with the invite-fixed handle and role.
+	if err := s.AddUser(signPub, inv.Handle, inv.Role); err != nil {
+		if errors.Is(err, ErrUserExists) {
+			return ErrUserExists
+		}
+		return fmt.Errorf("membership: consume invite %q: register user: %w", token, err)
+	}
+	return nil
+}
+
+func (s *jetstreamStore) CancelInvite(token string) error {
+	ctx, cancel := s.ctx()
+	defer cancel()
+	if _, err := s.invites.Get(ctx, token); err != nil {
+		if errors.Is(err, jetstream.ErrKeyNotFound) {
+			return fmt.Errorf("membership: cancel invite %q: %w", token, ErrNotFound)
+		}
+		return fmt.Errorf("membership: cancel invite %q: %w", token, err)
+	}
+	if err := s.invites.Delete(ctx, token); err != nil {
+		return fmt.Errorf("membership: cancel invite %q: %w", token, err)
+	}
+	return nil
+}
+
 // ---- snapshot import / export (issue 0003c migration) ---------------------
 
 // importSnapshot writes a full Snapshot into the KV buckets, preserving each

pkg/membership/migrations/003_invites.sql

@@ -0,0 +1,28 @@
+-- 003_invites.sql — single-use registration invites (issue: user accounts / wallet model).
+--
+-- An admin mints an invite so a brand-new identity can join the bus allowlist
+-- WITHOUT the admin ever handling its private key. The token is the bearer
+-- secret that authorizes POST /register: the registering client generates its
+-- keypair locally and publishes only its public keys, fixing the link between an
+-- invite and the identity it creates via the audit columns below. The handle and
+-- role are fixed by the admin at mint time and cannot be changed by the client
+-- (no privilege escalation).
+--
+-- Additive and idempotent: safe to apply repeatedly. Never modify this file;
+-- further schema changes go in new numbered migrations (see
+-- .claude/rules/db_migrations.md). The embedded copy under
+-- pkg/membership/migrations/003_invites.sql mirrors this file byte-for-byte.
+
+CREATE TABLE IF NOT EXISTS invites (
+  token         TEXT PRIMARY KEY,                -- 32 random bytes in lowercase hex (the bearer secret)
+  handle        TEXT NOT NULL,                   -- handle the new user will get (fixed by admin)
+  role          TEXT NOT NULL DEFAULT 'member',  -- 'admin' | 'member' (fixed by admin)
+  expires_at    TEXT NOT NULL,                   -- RFC3339; past this the invite is dead
+  used          INTEGER NOT NULL DEFAULT 0,      -- 0 pending, 1 consumed (single-use)
+  created_at    TEXT NOT NULL,
+  used_at       TEXT,                            -- RFC3339 when consumed (NULL until used)
+  used_sign_pub TEXT,                            -- Ed25519 key that consumed it (audit; NULL until used)
+  used_kex_pub  TEXT                             -- X25519 key presented at registration (audit; NULL until used)
+);
+
+CREATE INDEX IF NOT EXISTS idx_invites_used ON invites(used);

pkg/membership/server.go

@@ -144,9 +144,11 @@ func (s *Server) ServeHTTP(w http.ResponseWriter, r *http.Request) {
 	now := time.Now()
 
 	// Per-IP rate limit runs first, ahead of auth and body reads, so a flood is
-	// shed at the cheapest possible point. The health probe is exempt so liveness
-	// checks are never throttled.
-	if !isAuthExempt(r) && !s.limiter.allow(clientIP(r), now) {
+	// shed at the cheapest possible point. ONLY the health probe is exempt so
+	// liveness checks are never throttled — note this is isRateExempt, NOT
+	// isAuthExempt: POST /register is auth-exempt (no admin signature) but stays
+	// rate-limited, since it is the one un-signed path that mutates the allowlist.
+	if !isRateExempt(r) && !s.limiter.allow(clientIP(r), now) {
 		writeErr(w, http.StatusTooManyRequests, "rate limit exceeded")
 		return
 	}
@@ -213,9 +215,12 @@ func (s *Server) ServeHTTP(w http.ResponseWriter, r *http.Request) {
 		writeErr(w, http.StatusUnauthorized, "unauthorized: "+err.Error())
 		return
 	}
-	// Carry the authenticated signer's endpoint into the handler so room handlers
-	// can authorize by membership (audit H3). Only set on a verified identity.
-	s.mux.ServeHTTP(w, r.WithContext(withSigner(r.Context(), res.endpoint)))
+	// Carry the authenticated signer's endpoint AND signing key into the handler.
+	// Room handlers authorize by membership via the endpoint (audit H3); the
+	// user-management handlers authorize by role via the signing key (the endpoint
+	// id is a one-way hash of the key, so it cannot be reversed to look the signer
+	// up in the user allowlist). Both are set only on a verified identity.
+	s.mux.ServeHTTP(w, r.WithContext(withSigner(r.Context(), res.endpoint, res.pubHex)))
 }
 
 // isBodyTooLarge reports whether err is the sentinel returned by MaxBytesReader
@@ -229,11 +234,19 @@ func isBodyTooLarge(err error) bool {
 // values cannot collide with keys set by other packages.
 type ctxKey int
 
-const ctxSignerEndpoint ctxKey = iota
+const (
+	ctxSignerEndpoint ctxKey = iota
+	ctxSignerPub
+)
 
-// withSigner returns a context carrying the authenticated signer's endpoint id.
-func withSigner(ctx context.Context, endpoint string) context.Context {
-	return context.WithValue(ctx, ctxSignerEndpoint, endpoint)
+// withSigner returns a context carrying the authenticated signer's endpoint id
+// and signing public key (lowercase hex). The endpoint authorizes room
+// membership; the signing key authorizes user-management by role, because the
+// endpoint id is a one-way hash of the key (base64url(sha256(signPub))) and so
+// cannot be reversed to look the signer up in the user allowlist.
+func withSigner(ctx context.Context, endpoint, pubHex string) context.Context {
+	ctx = context.WithValue(ctx, ctxSignerEndpoint, endpoint)
+	return context.WithValue(ctx, ctxSignerPub, pubHex)
 }
 
 // signerEndpoint returns the authenticated signer's endpoint id and whether one
@@ -245,6 +258,16 @@ func signerEndpoint(r *http.Request) (string, bool) {
 	return v, ok && v != ""
 }
 
+// signerPubHex returns the authenticated signer's signing public key (lowercase
+// hex) and whether one is present. Like signerEndpoint it is absent under
+// AuthOff and on a soft-mode pass-through; the user-management handlers treat
+// that absence as "no admin identity" and deny (default-deny), since a
+// privilege-granting operation must never run without a verified admin.
+func signerPubHex(r *http.Request) (string, bool) {
+	v, ok := r.Context().Value(ctxSignerPub).(string)
+	return v, ok && v != ""
+}
+
 // requireMember authorizes a room request by membership (audit H3): it returns
 // the signer endpoint and true when the request may proceed, or writes 403 and
 // returns false when an authenticated signer is not a member of roomID. When no
@@ -262,13 +285,54 @@ func (s *Server) requireMember(w http.ResponseWriter, r *http.Request, roomID st
 	return signer, true
 }
 
-// isAuthExempt lists requests that bypass control-plane auth even under enforce.
-// Only the unauthenticated health probe qualifies: it carries no data and is
-// needed by load balancers / smoke checks / systemd before any identity exists.
-func isAuthExempt(r *http.Request) bool {
+// requireAdmin authorizes a user-management request: it returns the signer's
+// signing-key hex and true ONLY when the authenticated signer is a user with
+// role admin and active status; otherwise it writes 403 and returns false.
+//
+// Default-deny, with no dev relaxation: unlike requireMember (which allows a
+// request when no authenticated signer is present, preserving AuthOff/dev
+// behavior for room reads), this denies whenever the signer is absent or is not
+// a verified active admin. The user-management endpoints grant and revoke bus
+// access, so they must never be reachable without a verified admin identity —
+// the store is consulted on every call so a just-revoked admin is denied
+// immediately, and any store error fails closed.
+func (s *Server) requireAdmin(w http.ResponseWriter, r *http.Request) (string, bool) {
+	pubHex, ok := signerPubHex(r)
+	if !ok {
+		writeErr(w, http.StatusForbidden, "forbidden: admin role required")
+		return "", false
+	}
+	u, err := s.store.GetUser(pubHex)
+	if err != nil || u.Role != RoleAdmin || u.Status != StatusActive {
+		writeErr(w, http.StatusForbidden, "forbidden: admin role required")
+		return "", false
+	}
+	return pubHex, true
+}
+
+// isRateExempt lists requests that bypass the per-IP rate limiter. Only the
+// health probe qualifies: a load balancer / systemd / smoke check polls it and
+// must never be throttled. Everything else — including POST /register — is rate
+// limited.
+func isRateExempt(r *http.Request) bool {
 	return r.Method == http.MethodGet && r.URL.Path == "/healthz"
 }
 
+// isAuthExempt lists requests that bypass control-plane signature auth even under
+// enforce. Two qualify:
+//   - GET /healthz: carries no data, needed before any identity exists.
+//   - POST /register: the wallet-model join path. The registering identity is not
+//     yet in the allowlist, so it CANNOT produce an accepted admin signature;
+//     authorization is the single-use bearer invite token, validated inside the
+//     handler (ConsumeInvite). It stays rate-limited (see isRateExempt) and
+//     strictly validates the hex keys before spending the token.
+func isAuthExempt(r *http.Request) bool {
+	if r.Method == http.MethodGet && r.URL.Path == "/healthz" {
+		return true
+	}
+	return r.Method == http.MethodPost && r.URL.Path == "/register"
+}
+
 func (s *Server) routes() {
 	s.mux.HandleFunc("GET /healthz", s.handleHealth)
 	s.mux.HandleFunc("POST /rooms", s.handleCreateRoom)
@@ -280,6 +344,23 @@ func (s *Server) routes() {
 	s.mux.HandleFunc("GET /rooms/{id}", s.handleGetRoom)
 	s.mux.HandleFunc("POST /blobs", s.handlePutBlob)
 	s.mux.HandleFunc("GET /blobs/{hash}", s.handleGetBlob)
+	// User-management (admin-only) — the HTTP-signed equivalent of the local
+	// `membershipd user` CLI, so the admin panel manages the bus allowlist by
+	// signing as an admin instead of needing direct store/KV access. All three
+	// pass through requireAdmin; they hit the same store the room handlers do.
+	s.mux.HandleFunc("GET /users", s.handleListUsers)
+	s.mux.HandleFunc("POST /users", s.handleAddUser)
+	s.mux.HandleFunc("POST /users/{signpub}/revoke", s.handleRevokeUser)
+	// Hard-delete (purge) a user — distinct from revoke (status flip). Admin-only.
+	s.mux.HandleFunc("DELETE /users/{signpub}", s.handleDeleteUser)
+	// Invites — the wallet-model account-creation path. The admin mints a
+	// single-use link (POST /invites, admin-only); the new user's client redeems
+	// it without an admin signature (POST /register, token-authorized). Listing
+	// and cancelling a pending invite are admin-only.
+	s.mux.HandleFunc("POST /invites", s.handleCreateInvite)
+	s.mux.HandleFunc("GET /invites", s.handleListInvites)
+	s.mux.HandleFunc("DELETE /invites/{token}", s.handleCancelInvite)
+	s.mux.HandleFunc("POST /register", s.handleRegister)
 }
 
 // ---- wire types -----------------------------------------------------------
@@ -357,6 +438,67 @@ type blobResp struct {
 	Hash string `json:"hash"`
 }
 
+// userJSON is the wire representation of a bus user on the admin endpoints. It
+// carries the full record the panel needs to render the allowlist, including
+// status (so revoked users are visible) and the timestamps. revoked_at is
+// omitted for an active user.
+type userJSON struct {
+	SignPub   string `json:"sign_pub"`
+	Handle    string `json:"handle"`
+	Role      string `json:"role"`
+	Status    string `json:"status"`
+	CreatedAt string `json:"created_at"`
+	RevokedAt string `json:"revoked_at,omitempty"`
+}
+
+// addUserReq is the POST /users body: the new user's Ed25519 signing key
+// (64-hex), human handle, and role. role is optional and defaults to member.
+type addUserReq struct {
+	SignPub string `json:"sign_pub"`
+	Handle  string `json:"handle"`
+	Role    string `json:"role"`
+}
+
+// createInviteReq is the POST /invites body (admin-only): the handle and role the
+// future user will receive (fixed here, NOT chosen by the registering client) and
+// an optional TTL in seconds (non-positive uses the 7-day default).
+type createInviteReq struct {
+	Handle  string `json:"handle"`
+	Role    string `json:"role"`
+	TTLSecs int    `json:"ttl_secs"`
+}
+
+// createInviteResp is the POST /invites reply: the bearer token to put in the
+// join link and its absolute expiry. The token is shown ONCE here; the admin
+// copies the link immediately.
+type createInviteResp struct {
+	Token     string `json:"token"`
+	ExpiresAt string `json:"expires_at"`
+}
+
+// inviteJSON is the wire representation of a pending invite on GET /invites. It
+// omits the audit fields (used_*) because the listing is of pending invites only;
+// used_at is carried so a client can render "expires in N".
+type inviteJSON struct {
+	Token     string `json:"token"`
+	Handle    string `json:"handle"`
+	Role      string `json:"role"`
+	ExpiresAt string `json:"expires_at"`
+	Used      bool   `json:"used"`
+	CreatedAt string `json:"created_at"`
+}
+
+// registerReq is the POST /register body. It is the ONLY allowlist-mutating
+// request that carries no admin signature: the bearer Token authorizes it. The
+// client supplies its freshly-generated public keys (sign_pub = Ed25519 identity,
+// kex_pub = X25519 key-exchange), both 64-hex. The handle and role come from the
+// invite, never from this body — the client cannot escalate.
+type registerReq struct {
+	Token   string `json:"token"`
+	SignPub string `json:"sign_pub"`
+	KexPub  string `json:"kex_pub"`
+}
+
 // ---- helpers --------------------------------------------------------------
 
 func writeJSON(w http.ResponseWriter, code int, v any) {
@@ -674,3 +816,253 @@ func (s *Server) handleGetBlob(w http.ResponseWriter, r *http.Request) {
 	w.WriteHeader(http.StatusOK)
 	_, _ = w.Write(data)
 }
+
+// ---- user-management handlers (admin-only) --------------------------------
+
+// handleListUsers returns the full bus allowlist, including revoked users, so an
+// admin sees the complete picture (a revoked identity stays auditable). Admin-only.
+func (s *Server) handleListUsers(w http.ResponseWriter, r *http.Request) {
+	if _, ok := s.requireAdmin(w, r); !ok {
+		return
+	}
+	users, err := s.store.ListUsers()
+	if err != nil {
+		writeServerErr(w, r, http.StatusInternalServerError, "internal error", err)
+		return
+	}
+	out := make([]userJSON, 0, len(users))
+	for _, u := range users {
+		out = append(out, userJSON{
+			SignPub:   u.SignPub,
+			Handle:    u.Handle,
+			Role:      u.Role,
+			Status:    u.Status,
+			CreatedAt: u.CreatedAt,
+			RevokedAt: u.RevokedAt,
+		})
+	}
+	writeJSON(w, http.StatusOK, out)
+}
+
+// handleAddUser registers a new bus user from an admin-supplied Ed25519 signing
+// key. It mirrors the `membershipd user add` CLI: the key must be 64-hex, the
+// role must be admin or member (empty defaults to member), and re-adding an
+// already-registered key is a 409 that leaves the existing row untouched — no
+// silent upsert that could flip a role or clobber status. Admin-only.
+func (s *Server) handleAddUser(w http.ResponseWriter, r *http.Request) {
+	if _, ok := s.requireAdmin(w, r); !ok {
+		return
+	}
+	var req addUserReq
+	if err := json.NewDecoder(r.Body).Decode(&req); err != nil {
+		writeErr(w, http.StatusBadRequest, "bad json: "+err.Error())
+		return
+	}
+	if req.SignPub == "" || req.Handle == "" {
+		writeErr(w, http.StatusBadRequest, "sign_pub and handle required")
+		return
+	}
+	if err := ValidateSignPubHex(req.SignPub); err != nil {
+		writeErr(w, http.StatusBadRequest, err.Error())
+		return
+	}
+	role := req.Role
+	if role == "" {
+		role = RoleMember
+	}
+	if role != RoleAdmin && role != RoleMember {
+		writeErr(w, http.StatusBadRequest,
+			fmt.Sprintf("invalid role %q (want %q or %q)", role, RoleAdmin, RoleMember))
+		return
+	}
+	if err := s.store.AddUser(req.SignPub, req.Handle, role); err != nil {
+		if errors.Is(err, ErrUserExists) {
+			// Idempotency contract (mirrors the CLI): re-adding a key is an explicit,
+			// non-destructive conflict. To replace a user, revoke then add again.
+			writeErr(w, http.StatusConflict,
+				"user already registered (unchanged); revoke it first to replace")
+			return
+		}
+		writeServerErr(w, r, http.StatusInternalServerError, "internal error", err)
+		return
+	}
+	writeJSON(w, http.StatusCreated, map[string]string{"status": "added"})
+}
+
+// handleRevokeUser revokes a bus user by signing key. Revocation is a status
+// flip (no hard delete) so the identity stays auditable and IsAuthorized denies
+// it on both planes immediately. Revoking an unknown or already-revoked key is a
+// 404. Admin-only.
+func (s *Server) handleRevokeUser(w http.ResponseWriter, r *http.Request) {
+	if _, ok := s.requireAdmin(w, r); !ok {
+		return
+	}
+	signPub := r.PathValue("signpub")
+	if err := ValidateSignPubHex(signPub); err != nil {
+		writeErr(w, http.StatusBadRequest, err.Error())
+		return
+	}
+	if err := s.store.RevokeUser(signPub); err != nil {
+		writeServerErr(w, r, http.StatusNotFound, "no active user with that key", err)
+		return
+	}
+	writeJSON(w, http.StatusOK, map[string]string{"status": "revoked"})
+}
+
+// handleDeleteUser hard-deletes a bus user by signing key — the purge that the
+// admin panel's "Eliminar" (permanent) action maps to, distinct from revoke's
+// status flip. The row is removed entirely (no audit trail kept); use revoke when
+// an auditable record must remain. Deleting an unknown key is a 404. Admin-only.
+//
+// Security note: like revoke, this does NOT special-case the last admin — an
+// admin can delete the final admin and lock the HTTP user-management surface. The
+// recovery seam is the local `membershipd user add` CLI (which re-seeds an admin
+// directly against the store), the same chicken-egg breaker that seeds the first
+// admin.
+func (s *Server) handleDeleteUser(w http.ResponseWriter, r *http.Request) {
+	if _, ok := s.requireAdmin(w, r); !ok {
+		return
+	}
+	signPub := r.PathValue("signpub")
+	if err := ValidateSignPubHex(signPub); err != nil {
+		writeErr(w, http.StatusBadRequest, err.Error())
+		return
+	}
+	if err := s.store.DeleteUser(signPub); err != nil {
+		if errors.Is(err, ErrNotFound) {
+			writeErr(w, http.StatusNotFound, "no user with that key")
+			return
+		}
+		writeServerErr(w, r, http.StatusInternalServerError, "internal error", err)
+		return
+	}
+	writeJSON(w, http.StatusOK, map[string]string{"status": "deleted"})
+}
+
+// ---- invite handlers ------------------------------------------------------
+
+// handleCreateInvite mints a single-use registration invite. The handle and role
+// are fixed here by the admin; the role is validated (admin|member, empty ->
+// member) so an unknown role is a clean 400 rather than an opaque 500. The reply
+// carries the bearer token and its expiry — the admin turns the token into the
+// join link. Admin-only.
+func (s *Server) handleCreateInvite(w http.ResponseWriter, r *http.Request) {
+	if _, ok := s.requireAdmin(w, r); !ok {
+		return
+	}
+	var req createInviteReq
+	if err := json.NewDecoder(r.Body).Decode(&req); err != nil {
+		writeErr(w, http.StatusBadRequest, "bad json: "+err.Error())
+		return
+	}
+	if req.Handle == "" {
+		writeErr(w, http.StatusBadRequest, "handle required")
+		return
+	}
+	if req.Role != "" && req.Role != RoleAdmin && req.Role != RoleMember {
+		writeErr(w, http.StatusBadRequest,
+			fmt.Sprintf("invalid role %q (want %q or %q)", req.Role, RoleAdmin, RoleMember))
+		return
+	}
+	inv, err := s.store.CreateInvite(req.Handle, req.Role, req.TTLSecs)
+	if err != nil {
+		writeServerErr(w, r, http.StatusInternalServerError, "internal error", err)
+		return
+	}
+	writeJSON(w, http.StatusCreated, createInviteResp{Token: inv.Token, ExpiresAt: inv.ExpiresAt})
+}
+
+// handleListInvites returns the PENDING invites (not yet used and not expired), so
+// the admin panel shows only live links worth copying. Consumed/expired invites
+// are filtered out here rather than at the store, which exposes the full set for
+// other callers. Admin-only.
+func (s *Server) handleListInvites(w http.ResponseWriter, r *http.Request) {
+	if _, ok := s.requireAdmin(w, r); !ok {
+		return
+	}
+	invites, err := s.store.ListInvites()
+	if err != nil {
+		writeServerErr(w, r, http.StatusInternalServerError, "internal error", err)
+		return
+	}
+	out := make([]inviteJSON, 0, len(invites))
+	for _, inv := range invites {
+		if inv.Used || inviteIsExpired(inv.ExpiresAt) {
+			continue // pending only
+		}
+		out = append(out, inviteJSON{
+			Token:     inv.Token,
+			Handle:    inv.Handle,
+			Role:      inv.Role,
+			ExpiresAt: inv.ExpiresAt,
+			Used:      inv.Used,
+			CreatedAt: inv.CreatedAt,
+		})
+	}
+	writeJSON(w, http.StatusOK, out)
+}
+
+// handleCancelInvite cancels (hard-deletes) a pending invite, so an admin can
+// revoke a link before it is redeemed. Cancelling an unknown token is a 404.
+// Admin-only.
+func (s *Server) handleCancelInvite(w http.ResponseWriter, r *http.Request) {
+	if _, ok := s.requireAdmin(w, r); !ok {
+		return
+	}
+	token := r.PathValue("token")
+	if token == "" {
+		writeErr(w, http.StatusBadRequest, "token required")
+		return
+	}
+	if err := s.store.CancelInvite(token); err != nil {
+		if errors.Is(err, ErrNotFound) {
+			writeErr(w, http.StatusNotFound, "no such invite")
+			return
+		}
+		writeServerErr(w, r, http.StatusInternalServerError, "internal error", err)
+		return
+	}
+	writeJSON(w, http.StatusOK, map[string]string{"status": "cancelled"})
+}
+
+// handleRegister redeems an invite: the wallet-model join path. It is auth-exempt
+// (no admin signature; see isAuthExempt) but rate-limited and strictly validated.
+// The client presents the single-use token plus its freshly-generated public keys
+// (sign_pub Ed25519, kex_pub X25519). Both keys are validated as 64-hex BEFORE the
+// token is spent, the handle and role come from the invite (never this body), and
+// ConsumeInvite enforces single-use atomically. Errors map to precise codes so a
+// client can tell "unknown" from "used" from "expired".
+func (s *Server) handleRegister(w http.ResponseWriter, r *http.Request) {
+	var req registerReq
+	if err := json.NewDecoder(r.Body).Decode(&req); err != nil {
+		writeErr(w, http.StatusBadRequest, "bad json: "+err.Error())
+		return
+	}
+	if req.Token == "" {
+		writeErr(w, http.StatusBadRequest, "token required")
+		return
+	}
+	if err := ValidateSignPubHex(req.SignPub); err != nil {
+		writeErr(w, http.StatusBadRequest, err.Error())
+		return
+	}
+	if err := ValidateKexPubHex(req.KexPub); err != nil {
+		writeErr(w, http.StatusBadRequest, err.Error())
+		return
+	}
+	err := s.store.ConsumeInvite(req.Token, req.SignPub, req.KexPub)
+	switch {
+	case err == nil:
+		writeJSON(w, http.StatusCreated, map[string]string{"status": "registered"})
+	case errors.Is(err, ErrNotFound):
+		writeErr(w, http.StatusNotFound, "invalid or unknown invite token")
+	case errors.Is(err, ErrInviteUsed):
+		writeErr(w, http.StatusConflict, "invite already used")
+	case errors.Is(err, ErrInviteExpired):
+		writeErr(w, http.StatusGone, "invite expired")
+	case errors.Is(err, ErrUserExists):
+		writeErr(w, http.StatusConflict, "identity already registered")
+	default:
+		writeServerErr(w, r, http.StatusInternalServerError, "internal error", err)
+	}
+}

pkg/membership/store.go

@@ -80,9 +80,23 @@ type Store interface {
 	GetUser(signPub string) (User, error)
 	ListUsers() ([]User, error)
 	RevokeUser(signPub string) error
+	// DeleteUser hard-deletes a user (the purge counterpart of RevokeUser's
+	// status flip): the row is removed, not just flagged. The ex-user can no
+	// longer authenticate, so any room memberships they hold become inert.
+	DeleteUser(signPub string) error
 	IsAuthorized(signPub string) bool
 	HasAdmin() bool
 
+	// Invites (single-use registration tokens; the wallet-model join path).
+	// CreateInvite mints a token fixing handle+role; ConsumeInvite is the only
+	// path that adds to the allowlist without an admin signature (the bearer
+	// token is the authorization), spending the token exactly once.
+	CreateInvite(handle, role string, ttlSecs int) (Invite, error)
+	GetInvite(token string) (Invite, error)
+	ListInvites() ([]Invite, error)
+	ConsumeInvite(token, signPub, kexPub string) error
+	CancelInvite(token string) error
+
 	// Lifecycle.
 	Close() error
 }

pkg/membership/users.go

@@ -2,6 +2,7 @@ package membership
 
 import (
 	"database/sql"
+	"encoding/hex"
 	"errors"
 	"fmt"
 	"strings"
@@ -35,6 +36,40 @@ type User struct {
 	RevokedAt string // empty unless revoked
 }
 
+// ValidateSignPubHex ensures signPub is exactly a 32-byte Ed25519 public key in
+// hex (64 hex chars). It is the single source of truth for that check, shared by
+// the local admin CLI (which validates before seeding the first admin) and the
+// HTTP user-management handlers (which validate an admin-supplied key before it
+// reaches the store). Catching a malformed key here turns a silent "authorized
+// nobody" into an explicit error at the boundary.
+func ValidateSignPubHex(signPub string) error {
+	b, err := hex.DecodeString(signPub)
+	if err != nil {
+		return fmt.Errorf("sign-pub is not valid hex: %w", err)
+	}
+	if len(b) != 32 {
+		return fmt.Errorf("sign-pub must be a 32-byte Ed25519 public key (64 hex chars), got %d bytes", len(b))
+	}
+	return nil
+}
+
+// ValidateKexPubHex ensures kexPub is exactly a 32-byte X25519 public key in hex
+// (64 hex chars). It is the registration-side counterpart of ValidateSignPubHex:
+// POST /register receives both the new identity's signing key and its key-exchange
+// key, and both must be well-formed before the invite is consumed. An X25519
+// public key is 32 bytes, identical in length to Ed25519, so the check is the
+// same shape with a key-exchange-specific message.
+func ValidateKexPubHex(kexPub string) error {
+	b, err := hex.DecodeString(kexPub)
+	if err != nil {
+		return fmt.Errorf("kex-pub is not valid hex: %w", err)
+	}
+	if len(b) != 32 {
+		return fmt.Errorf("kex-pub must be a 32-byte X25519 public key (64 hex chars), got %d bytes", len(b))
+	}
+	return nil
+}
+
 // normalizeSignPub lowercases the hex key so lookups are case-insensitive: the
 // primary key is stored lowercase and every query normalizes its input the same
 // way, so a caller passing uppercase hex still matches.
@@ -72,8 +107,10 @@ func (s *sqliteStore) AddUser(signPub, handle, role string) error {
 	return nil
 }
 
-// GetUser returns the user with the given signing public key. It returns
-// sql.ErrNoRows (wrapped) when there is no such user.
+// GetUser returns the user with the given signing public key. A miss returns
+// ErrNotFound (wrapped), matching the storage-agnostic contract in store.go and
+// the JetStream backend, so callers can branch on ErrNotFound regardless of which
+// store is active (the SQLite-specific sql.ErrNoRows is mapped here).
 func (s *sqliteStore) GetUser(signPub string) (User, error) {
 	signPub = normalizeSignPub(signPub)
 	var u User
@@ -83,6 +120,9 @@ func (s *sqliteStore) GetUser(signPub string) (User, error) {
 		signPub,
 	).Scan(&u.SignPub, &u.Handle, &u.Role, &u.Status, &u.CreatedAt, &revoked)
 	if err != nil {
+		if errors.Is(err, sql.ErrNoRows) {
+			return User{}, fmt.Errorf("membership: get user %q: %w", signPub, ErrNotFound)
+		}
 		return User{}, fmt.Errorf("membership: get user %q: %w", signPub, err)
 	}
 	u.RevokedAt = revoked.String
@@ -135,6 +175,31 @@ func (s *sqliteStore) RevokeUser(signPub string) error {
 	return nil
 }
 
+// DeleteUser hard-deletes a user from the allowlist (admin "remove user", the
+// purge counterpart of RevokeUser's status flip). It removes ONLY the allowlist
+// row: the ex-user can no longer authenticate on either plane, so any room
+// memberships they still hold become inert (they cannot fetch a sealed key, sign
+// a request, or open a NATS connection). We deliberately do NOT chase down and
+// rewrite those room memberships here — that would be a partial, racy cleanup of
+// state owned by each room's owner; a room owner kicks/rekeys to achieve forward
+// secrecy when needed. Deleting an unknown key returns ErrNotFound (wrapped) so
+// the HTTP layer can answer 404.
+func (s *sqliteStore) DeleteUser(signPub string) error {
+	signPub = normalizeSignPub(signPub)
+	res, err := s.db.Exec(`DELETE FROM users WHERE sign_pub = ?`, signPub)
+	if err != nil {
+		return fmt.Errorf("membership: delete user %q: %w", signPub, err)
+	}
+	n, err := res.RowsAffected()
+	if err != nil {
+		return fmt.Errorf("membership: delete user %q: rows affected: %w", signPub, err)
+	}
+	if n == 0 {
+		return fmt.Errorf("membership: delete user %q: %w", signPub, ErrNotFound)
+	}
+	return nil
+}
+
 // IsAuthorized reports whether signPub belongs to an active (non-revoked) bus
 // user. It is the single authorization predicate consulted by both the control
 // plane (HTTP request middleware) and the data plane (NATS nkey authenticator),

pkg/membership/users_http_test.go

@@ -0,0 +1,164 @@
+package membership
+
+import (
+	"encoding/hex"
+	"encoding/json"
+	"net/http"
+	"testing"
+	"time"
+
+	cs "fn-registry/functions/cybersecurity"
+)
+
+// signedJSON is signedReq for a JSON body: it marshals v and signs the request
+// as id with a distinct nonce. It returns the response status and body, reusing
+// the auth_test harness so these tests exercise the real signed wire contract.
+func signedJSON(t *testing.T, h *authHarness, method, path string, v any, id cs.Identity, n int) (int, string) {
+	t.Helper()
+	var body []byte
+	if v != nil {
+		b, err := json.Marshal(v)
+		if err != nil {
+			t.Fatalf("marshal body: %v", err)
+		}
+		body = b
+	}
+	return do(t, signedReq(t, h.ts.URL, method, path, body, id, time.Now().Unix(), nonceN(n)))
+}
+
+// TestUsersHTTP_NonAdminForbidden is the security spine: a REGISTERED but
+// non-admin signer (bob, role member) is denied on every user-management
+// endpoint. His signature clears auth (he is in the allowlist), so each request
+// reaches the handler, where requireAdmin returns 403 — default-deny by role.
+func TestUsersHTTP_NonAdminForbidden(t *testing.T) {
+	h := newAuthHarness(t, AuthEnforce)
+
+	bob, _ := cs.GenerateIdentity()
+	register(t, h, bob, "bob") // role member (see register in authz_test.go)
+	bobPub := hex.EncodeToString(bob.SignPub)
+
+	victim, _ := cs.GenerateIdentity()
+	victimPub := hex.EncodeToString(victim.SignPub)
+
+	checks := []struct {
+		name   string
+		method string
+		path   string
+		body   any
+	}{
+		{"list users", "GET", "/users", nil},
+		{"add user", "POST", "/users", addUserReq{SignPub: victimPub, Handle: "mallory", Role: RoleMember}},
+		{"revoke user", "POST", "/users/" + bobPub + "/revoke", nil},
+	}
+	for i, c := range checks {
+		code, body := signedJSON(t, h, c.method, c.path, c.body, bob, i+1)
+		if code != http.StatusForbidden {
+			t.Fatalf("non-admin %s should be 403, got %d (%s)", c.name, code, body)
+		}
+	}
+}
+
+// TestUsersHTTP_AdminRoundtrip exercises the golden path end to end: alice (the
+// seeded admin) adds carol, sees her in the list as active, revokes her, then
+// sees her status flip to revoked (no hard delete — she stays in the list).
+func TestUsersHTTP_AdminRoundtrip(t *testing.T) {
+	h := newAuthHarness(t, AuthEnforce)
+
+	carol, _ := cs.GenerateIdentity()
+	carolPub := hex.EncodeToString(carol.SignPub)
+
+	// Add carol as a member.
+	if code, body := signedJSON(t, h, "POST", "/users",
+		addUserReq{SignPub: carolPub, Handle: "carol", Role: RoleMember}, h.alice, 1); code != http.StatusCreated {
+		t.Fatalf("admin add carol should be 201, got %d (%s)", code, body)
+	}
+
+	// List: carol present and active; alice (the seed admin) also present.
+	users := listUsers(t, h, 2)
+	carolRow, ok := findUser(users, carolPub)
+	if !ok {
+		t.Fatalf("carol missing from list after add: %+v", users)
+	}
+	if carolRow.Status != StatusActive || carolRow.Role != RoleMember || carolRow.Handle != "carol" {
+		t.Fatalf("carol row wrong after add: %+v", carolRow)
+	}
+	if _, ok := findUser(users, h.alicePub); !ok {
+		t.Fatalf("seeded admin alice missing from list: %+v", users)
+	}
+
+	// Revoke carol.
+	if code, body := signedJSON(t, h, "POST", "/users/"+carolPub+"/revoke", nil, h.alice, 3); code != http.StatusOK {
+		t.Fatalf("admin revoke carol should be 200, got %d (%s)", code, body)
+	}
+
+	// List again: carol still present, now revoked (status flip, not delete).
+	users = listUsers(t, h, 4)
+	carolRow, ok = findUser(users, carolPub)
+	if !ok {
+		t.Fatalf("carol vanished from list after revoke (should be a status flip): %+v", users)
+	}
+	if carolRow.Status != StatusRevoked {
+		t.Fatalf("carol should be revoked, got status %q", carolRow.Status)
+	}
+}
+
+// TestUsersHTTP_Validation covers the input-validation contract: a malformed hex
+// key is 400, an unknown role is 400, and re-adding an already-registered key is
+// 409 (the existing row is left untouched — no silent upsert).
+func TestUsersHTTP_Validation(t *testing.T) {
+	h := newAuthHarness(t, AuthEnforce)
+
+	good, _ := cs.GenerateIdentity()
+	goodPub := hex.EncodeToString(good.SignPub)
+
+	// Invalid hex (too short) -> 400.
+	if code, body := signedJSON(t, h, "POST", "/users",
+		addUserReq{SignPub: "abcd", Handle: "shorty", Role: RoleMember}, h.alice, 1); code != http.StatusBadRequest {
+		t.Fatalf("malformed sign_pub should be 400, got %d (%s)", code, body)
+	}
+
+	// Invalid role -> 400.
+	if code, body := signedJSON(t, h, "POST", "/users",
+		addUserReq{SignPub: goodPub, Handle: "weirdrole", Role: "superuser"}, h.alice, 2); code != http.StatusBadRequest {
+		t.Fatalf("invalid role should be 400, got %d (%s)", code, body)
+	}
+
+	// Re-adding the seeded admin's own key -> 409 (idempotency, no overwrite).
+	if code, body := signedJSON(t, h, "POST", "/users",
+		addUserReq{SignPub: h.alicePub, Handle: "alice-again", Role: RoleMember}, h.alice, 3); code != http.StatusConflict {
+		t.Fatalf("re-adding an existing key should be 409, got %d (%s)", code, body)
+	}
+	// And the existing row is untouched: alice is still an active admin.
+	u, err := h.store.GetUser(h.alicePub)
+	if err != nil {
+		t.Fatalf("get alice after conflicting re-add: %v", err)
+	}
+	if u.Role != RoleAdmin || u.Status != StatusActive || u.Handle != "alice" {
+		t.Fatalf("conflicting re-add mutated the existing row: %+v", u)
+	}
+}
+
+// listUsers signs a GET /users as alice and decodes the response.
+func listUsers(t *testing.T, h *authHarness, n int) []userJSON {
+	t.Helper()
+	code, body := signedJSON(t, h, "GET", "/users", nil, h.alice, n)
+	if code != http.StatusOK {
+		t.Fatalf("admin list users should be 200, got %d (%s)", code, body)
+	}
+	var users []userJSON
+	if err := json.Unmarshal([]byte(body), &users); err != nil {
+		t.Fatalf("decode users: %v (%s)", err, body)
+	}
+	return users
+}
+
+// findUser returns the row with the given signing key (case-insensitive).
+func findUser(users []userJSON, signPub string) (userJSON, bool) {
+	want := normalizeSignPub(signPub)
+	for _, u := range users {
+		if normalizeSignPub(u.SignPub) == want {
+			return u, true
+		}
+	}
+	return userJSON{}, false
+}