Phase 5: Notifications — WebSocket, APScheduler, AI tool, health review

Backend:
- Notification model + Alembic migration
- Notification service: CRUD, mark read, unread count, pending scheduled
- WebSocket manager singleton for real-time push
- WebSocket endpoint /ws/notifications with JWT auth via query param
- APScheduler integration: periodic notification sender (every 60s),
  daily proactive health review job (8 AM)
- AI tool: schedule_notification (immediate or scheduled)
- Health review worker: analyzes user memory via Claude, creates
  ai_generated notifications with WebSocket push

Frontend:
- Notification API client + Zustand store
- WebSocket hook with auto-reconnect (exponential backoff)
- Notification bell in header with unread count badge + dropdown
- Notifications page with type badges, mark read, mark all read
- WebSocket initialized in AppLayout for app-wide real-time updates
- Enabled notifications nav in sidebar
- English + Russian translations

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

GeneralPlan.md

@@ -228,8 +228,8 @@ Daily scheduled job (APScheduler, 8 AM) reviews each user's memory + recent docs
 - Summary: Documents + memory tables, upload + processing pipeline, full-text search, AI tools (save_memory, search_documents, get_memory), frontend document/memory UI
 
 ### Phase 5: Notifications
-- **Status**: NOT STARTED
-- [ ] Subplan created (`plans/phase-5-notifications.md`)
+- **Status**: IN PROGRESS
+- [x] Subplan created (`plans/phase-5-notifications.md`)
 - [ ] Phase completed
 - Summary: Notifications table, WebSocket + email + Telegram channels, APScheduler, AI schedule_notification tool, proactive health review job, frontend notification UI