feat: initial implementation of agents_dashboard v0.1.0

Panels: Connection + Agents + Logs + Status Feed.
- HTTP GET /agents + POST /agents/{id}/{start,stop,restart}
- SSE streaming: /sse/agents/{id}/logs + /sse/status
- DPAPI/XOR credential storage in local_files/agents_dashboard.db
- data_table style agents table with filter + status icons
- SQLite migrations via sqlite3_exec at startup
- --self-test mode: db + secret_store round-trip + subsystem checks
- pytest mock server emulating agents_and_robots API

Registry functions: http_request_cpp_core, sse_client_cpp_core,
  secret_store_cpp_infra, logger_cpp_core
App icon: robot phosphor violet-500 (#8b5cf6)

Issue: 0129
Co-Authored-By: fn-orquestador <noreply@fn-registry.local>

app.md

@@ -0,0 +1,79 @@
+---
+name: agents_dashboard
+lang: cpp
+domain: tools
+description: "Frontend C++ ImGui para gestionar agentes Matrix (agents_and_robots) via HTTPS+apikey, SSE para logs/status en vivo"
+icon:
+  phosphor: "robot"
+  accent: "#8b5cf6"
+tags: [agents, dashboard, sse, http-client, imgui]
+version: 0.1.0
+uses_functions:
+  - http_request_cpp_core
+  - http_get_json_cpp_core
+  - sse_client_cpp_core
+  - secret_store_cpp_infra
+  - logger_cpp_core
+uses_types: []
+framework: "imgui"
+entry_point: "main.cpp"
+dir_path: "projects/element_agents/apps/agents_dashboard"
+repo_url: "https://gitea.organic-machine.com/dataforge/agents_dashboard"
+e2e_checks:
+  - id: build
+    cmd: "cmake --build /home/lucas/fn_registry/cpp/build/windows --target agents_dashboard -j"
+    timeout_s: 180
+  - id: self_test
+    cmd: "/home/lucas/fn_registry/cpp/build/windows/apps/agents_dashboard/agents_dashboard.exe --self-test"
+    timeout_s: 30
+  - id: pytest_mock
+    cmd: "cd /home/lucas/fn_registry/projects/element_agents/apps/agents_dashboard/tests && python3 -m pytest -x -q"
+    timeout_s: 60
+---
+
+# agents_dashboard
+
+Frontend C++ ImGui para gestionar agentes Matrix de agents_and_robots via HTTPS + apikey. SSE para logs y status feed en vivo.
+
+## Panels
+
+- **Connection** — base_url + apikey input (masked), Test button, LED status SSE. Save credentials cifradas en `local_files/agents_dashboard.db`.
+- **Agents** — tabla con id, status (icon colored), uptime, msg_24h, botones Start/Stop/Restart/Logs por fila.
+- **Logs** — selector agente + tail buffer SSE (5000 lineas), autoscroll, pause.
+- **Status Feed** — panel colapsable con eventos del `/sse/status` en tiempo real.
+
+## Persistencia
+
+- `local_files/agents_dashboard.db` (SQLite) — tabla `connections` (apikey cifrada DPAPI/XOR), `app_state`.
+- Migraciones en `migrations/001_init.sql` aplicadas via sqlite3_exec al arrancar.
+
+## Build
+
+```bash
+cmake --build cpp/build/windows --target agents_dashboard -j
+```
+
+## Deploy local (Windows)
+
+```bash
+./fn run redeploy_cpp_app_windows agents_dashboard projects/element_agents/apps/agents_dashboard --build
+```
+
+## Self-test
+
+```bash
+./cpp/build/windows/apps/agents_dashboard/agents_dashboard.exe --self-test
+# exit 0: db OK, secret_store round-trip OK, subsystems OK
+```
+
+## Registry functions used
+
+- `http_request_cpp_core` — GET/POST /agents + /agents/{id}/{action}
+- `http_get_json_cpp_core` — /health check
+- `sse_client_cpp_core` — /sse/agents/{id}/logs + /sse/status
+- `secret_store_cpp_infra` — DPAPI Windows / XOR Linux para apikey en SQLite
+- `logger_cpp_core` — logging en memoria + archivo
+
+## Capability growth log
+
+v0.1.0 (2026-05-22) — Paneles Connection + Agents + Logs + Status Feed. HTTPS+apikey, SSE reconnect, DPAPI credentials.