Docs audit: fix outdated references (PostgreSQL, Vue client, profiles, tools) ...

- architecture.md: SQLite → PostgreSQL + pgvector
- README.md: vanilla JS → Vue 3 + Pinia, remove smart_home, update temps
- profiles.md: remove smart_home, add discuss, update temperatures
- tools.md: add missing built-in tools, update user tools list
- sessions.md: fix outdated references
- NAVI.md: sync with current stack
- persona.txt: update self-extension and content_publish guidance
- content_publish.md manual: reflect session_dir-based no-copy design
- content_store.py & content_publish.py: inline with docs

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

Comprehensive documentation update ...

- websocket.md: add heartbeat, session_sync, replay_start/end, planning_status,
  plan_ready (with is_subagent), stream_end extra fields, context_compressed summary,
  updated _AgentRun.events replay buffer, corrected reconnect section
- sessions.md: add name, planning_logs fields; message flags (is_plan, is_compression,
  is_summary, thinking); set_name store op; debug endpoints section
- api.md: full rewrite — add generate-name, planning, file download endpoints;
  all missing WS events; correct message field table with is_plan/is_compression
- tools.md: update user tools list with all current tools
- index.md: fix profiles list (smart_home → developer)
- CLAUDE.md: add Documentation section with table of all docs files
- NAVI.md: add architecture.md entry, improve websocket description

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

Add backend documentation ...

10 markdown files covering all backend subsystems: architecture,
agent loop, tool system, sessions, WebSocket protocol, profiles,
memory, config, and API reference. Structured for AI readability
with a single entry point (docs/index.md) and cross-references.

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