Make server I/O non-blocking; update docs ...

- Wrap all heavy filesystem ops in asyncio.to_thread: filesystem tool
  (read/write/append/list/find/info/move/delete/query/smart_edit),
  image_view (read_bytes), share_file (shutil.copy2), write_tool
  (write_text, _register_user_tool), session_files (shutil.rmtree,
  iterdir), sessions upload endpoint (sync open/write → to_thread)
- Make delete_session_dir async; update its caller in sessions.py
- docs/config.md: fix wrong defaults (threshold 0.70, keep_recent 8),
  remove phantom SESSION_FILES_TTL_HOURS, add LLM timeouts, DATABASE_URL,
  PUBLIC_URL, Gmail, CONTEXT_SUMMARY_MAX_TOKENS sections
- docs/profiles.md: add missing tool_developer profile to table
- android-client: add WebView remote debugging; remove unused toolbar menu
- Remove stale helper scripts and test files

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

Add Android WebView client (android-client/) ...

Thin Android shell that loads the Navi web interface from a configured
server URL. All UI served from the server — no local assets, no rebuild
needed for interface updates.

Features:
- First-launch setup screen to enter server URL (stored in SharedPreferences)
- On connection error: clears saved URL so next launch re-asks
- Full-screen WebView, no toolbar
- Camera + gallery + file picker via WebChromeClient.onShowFileChooser
- HTTP cleartext enabled for local network access
- targetSdk 34 to avoid forced edge-to-edge on Android 15
- Adaptive icon: logo SVG converted to Android vector drawable

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