feat(rcal): add Google Calendar sync integration with connectors menu
- Google Calendar API client (server/google-calendar.ts): token auto-refresh,
list calendars, fetch events with incremental sync, create events, mapping
- OAuth scopes: added calendar.readonly + calendar.events, returnTo param
- rCal routes: subscribe, sync, sync-all, unsubscribe, push-to-Google endpoints
- Background sync loop: 10-minute interval with incremental sync tokens
- Frontend: calendar picker modal, sync button, per-event Google export
- MCP: source_type filter on rcal_list_events, new rcal_sync_google tool
- Connectors menu: Google shows services (Docs/Drive/Calendar) + calendar count,
added Obsidian & Logseq as file-based connectors, Notion shows services
- Fix: import-export dialog API base corrected from rnotes to rdocs
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>