Use gnexus-ui-kit semantic colors for device status dot and add state components ...

- Status dot in DeviceTable now uses .text-success / .text-danger from
  gnexus-ui-kit with currentColor for background and glow instead of
  project-specific CSS vars.
- Add DeviceChannelsState component for per-channel state rendering.
- Add loadStatesFor helper in devices store for targeted state loading.
- Record styling rule in CLAUDE.md: always prefer kit color classes.

Webclient. Areas favorites feature ...

- Added FavoritesStore (localStorage) for saving favorite areas
- New /areas/favorites screen with unstar button and empty state
- Star toggle button on areas tree screen
- Fixed sidebar hidden on areas-tree screen
- Set /areas/favorites as default areas page
- Fixed docs/device-spec.md duplicate section number
- Updated CLAUDE.md build instructions

Docs. Architecture, server API reference, dev guides. Tools moved to tools/