profiles: teach the agent to scout profiles and tools before switching ...

Persona gains a reconnaissance order (list_profiles, then list_tools for the
real toolset, then tool_manual) and the switch-vs-delegate rule: switch when
the task itself is another profile's work, delegate a side piece with
spawn_agent. The profiles block is built in one place and shared with the
admin prompt debug view, and the stale 'next user message' claim is fixed.

list_tools applies the admin-only role gate to an explicitly named profile,
the same one list_profiles uses, so it cannot enumerate hidden profiles.

Clean up SQLite references in docs and prompts after removal ...

- docs/index.md: PostgreSQL via asyncpg
- docs/memory.md: drop aiosqlite fallback mention
- docs/sessions.md: replace SqliteSessionStore with PgSessionStore docs
- webclient/docs/architecture.md: PostgreSQL only
- navi/profiles/tool_developer/system_prompt.txt: remove aiosqlite from available imports
- .gitignore: add .codex and *.db
- No remaining sqlite/aiosqlite/db_path references in codebase

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

Migrate to Vue webclient; rename old client to old_webclient ...

- client/ → old_webclient/ (vanilla JS client preserved as reference)
- webclient/ — new Vue 3 + Pinia webclient (source + dist build)
- vite.config.js: outDir changed to webclient/dist/
- main.py: serve /assets and /images from webclient/dist/,
  index.html from webclient/dist/index.html
- .gitignore: exclude webclient/node_modules/, include webclient/dist/

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>