feat(doctor): add fn doctor CLI + 14 functions for system management

Adds `fn doctor` read-only diagnostic command with subcommands artefacts,
services, sync, uses-functions, unused, and --json flag for agents.
Each subcommand wraps a registry function in functions/infra/.

New functions:
- artefact_doctor, services_status, pc_locations_drift,
  audit_uses_functions, find_unused_functions (Go diagnostics)
- backup_sqlite_db, rotate_backups, wait_for_http, wait_for_port,
  port_kill, tail_journal, pre_commit_hook_install (bash utilities)
- notify_telegram (Go HTTP)
- backup_all pipeline (tag launcher)

Plus prior session leftovers (scan_secrets_in_dirty, append_diary_entry,
git utilities, http_session_cookie_middleware, compile/full-git pipelines).

Fixes pc_locations_drift filepath.Join bug with absolute dir_path.
Documents fn doctor in CLAUDE.md, .claude/rules/fn_doctor.md (rule 23),
docs/architecture.md, CHANGELOG.md (2026-05-07), and diary entry.

First fn doctor uses-functions run found drift in 7/12 apps (deuda
para sincronizar app.md con imports reales).

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

bash/functions/infra/tbd_branch_create.md

@@ -0,0 +1,53 @@
+---
+name: tbd_branch_create
+kind: function
+lang: bash
+domain: infra
+version: "1.0.0"
+purity: impure
+signature: "tbd_branch_create(mode: string, ...args: string) -> void"
+description: "Crea una rama TBD (trunk-based development) desde master/main actualizado. Soporta modos 'issue <NNNN> <slug>' y 'quick <slug>'. Autodetecta la rama base (master/main), verifica working tree limpio, hace pull --rebase y crea la rama. Valida formato de numero de issue (4 digitos) y slug (kebab-case ASCII)."
+tags: [git, tbd, branch, trunk-based-development, workflow]
+uses_functions: []
+uses_types: []
+returns: []
+returns_optional: false
+error_type: "error_go_core"
+imports: []
+params:
+  - name: mode
+    desc: "Modo de creacion: 'issue' para ramas issue/<NNNN>-<slug> o 'quick' para ramas quick/<slug>."
+  - name: args
+    desc: "Para mode=issue: NNNN (4 digitos) + slug (kebab-case). Para mode=quick: solo slug (kebab-case)."
+output: "Crea la rama y cambia a ella. Imprime confirmacion a stdout. Exit 1 en caso de error (dirty tree, formato invalido, repo inexistente)."
+tested: true
+tests:
+  - "issue branch created"
+  - "quick branch created"
+  - "issue number must be 4 digits"
+  - "slug must be kebab-case"
+  - "invalid mode exits 1"
+  - "no args exits 1"
+  - "dirty tree exits 1"
+  - "existing branch exits 1"
+  - "works with main as base"
+test_file_path: "bash/functions/infra/tbd_branch_create.sh"
+file_path: "bash/functions/infra/tbd_branch_create.sh"
+---
+
+## Ejemplo
+
+```bash
+# Crear rama para un issue
+tbd_branch_create issue 0042 add-auth
+
+# Crear rama para cambio rapido
+tbd_branch_create quick fix-typo-readme
+
+# Ejecutar suite de tests
+bash bash/functions/infra/tbd_branch_create.sh --test
+```
+
+## Notas
+
+La funcion autodetecta la rama base probando primero `master` y luego `main` con `git show-ref --verify`. Si el directorio actual no es un repo git, sale con error. Si el working tree tiene cambios no commiteados, sale con error antes de hacer pull. Los tests internos se ejecutan con `--test` y crean repos temporales aislados con `mktemp -d`.