Update all documentation to reflect features added since last doc update:
- README: new features list, gallery screenshots, development status
- User Guide: global search, console commands, device dashboard, settings,
system log, backup, updated DM and contact management sections
- Architecture: complete API reference, WebSocket namespaces, updated
project structure and database tables
- Troubleshooting: remove v1 bridge references, add UI-based backup,
system log references
- Gallery: add 4 new screenshots (search, filtering, settings, system log),
update 12 existing screenshots
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
