- README: add Web UI Dashboard section, update features list with all
current capabilities (multi-channel, media pipeline, sandboxing, etc.),
expand model providers table, update architecture diagram
- CHANGELOG: add P7 entries (dashboard SPA, 4 new gateway handlers)
- state.json: add P7 entry with all 6 phases and file lists, update
overall_progress to reflect P0-P7 completion
- web-ui-dashboard.md: mark as completed with detailed phase outcomes
- Add SPA shell with hash-based router, sidebar navigation, and WebSocket RPC client
- Add dashboard page with system health cards, channel status, and auto-refresh
- Add chat page with session selector, streaming tool events, and markdown rendering
- Add sessions page with list, history viewer, and delete functionality
- Add settings page with hook pattern editor, tool list, and config viewer
- Add backend handlers: sessions.delete, sessions.switch, system.channels, system.usage
- Wire channelRegistry into gateway server for channel status reporting
- Extend static file server with .mjs, .png, .ico, .woff2 content types
William Valentin