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>

backend/app/workers/health_review.py

@@ -0,0 +1,83 @@
+"""Daily job: proactive health review for all users with health data."""
+import asyncio
+import logging
+
+from anthropic import AsyncAnthropic
+from sqlalchemy import select
+
+from app.config import settings
+from app.database import async_session_factory
+from app.models.user import User
+from app.services.memory_service import get_critical_memories
+from app.services.notification_service import create_notification
+from app.services.ws_manager import manager
+
+logger = logging.getLogger(__name__)
+client = AsyncAnthropic(api_key=settings.ANTHROPIC_API_KEY)
+
+
+async def run_daily_health_review():
+    """Review each user's health profile and generate reminder notifications."""
+    if not settings.ANTHROPIC_API_KEY:
+        return
+
+    async with async_session_factory() as db:
+        result = await db.execute(select(User).where(User.is_active == True))  # noqa: E712
+        users = result.scalars().all()
+
+    for user in users:
+        try:
+            await _review_user(user)
+            await asyncio.sleep(1)  # Rate limit
+        except Exception:
+            logger.exception(f"Health review failed for user {user.id}")
+
+
+async def _review_user(user: User):
+    async with async_session_factory() as db:
+        memories = await get_critical_memories(db, user.id)
+        if not memories:
+            return
+
+        memory_text = "\n".join(f"- [{m.category}] {m.title}: {m.content}" for m in memories)
+
+        response = await client.messages.create(
+            model=settings.CLAUDE_MODEL,
+            max_tokens=500,
+            system="You are a health assistant. Based on the user's health profile, suggest any upcoming checkups, medication reviews, or health actions that should be reminded. Respond with a JSON array of objects with 'title' and 'body' fields. If no reminders are needed, return an empty array [].",
+            messages=[{"role": "user", "content": f"User health profile:\n{memory_text}"}],
+        )
+
+        import json
+        try:
+            text = response.content[0].text.strip()
+            # Extract JSON from response
+            if "[" in text:
+                json_str = text[text.index("["):text.rindex("]") + 1]
+                reminders = json.loads(json_str)
+            else:
+                return
+        except (json.JSONDecodeError, ValueError):
+            return
+
+        for reminder in reminders[:5]:  # Max 5 reminders per user per day
+            if "title" in reminder and "body" in reminder:
+                notif = await create_notification(
+                    db,
+                    user.id,
+                    title=reminder["title"],
+                    body=reminder["body"],
+                    type="ai_generated",
+                )
+                await db.commit()
+
+                await manager.send_to_user(user.id, {
+                    "type": "new_notification",
+                    "notification": {
+                        "id": str(notif.id),
+                        "title": notif.title,
+                        "body": notif.body,
+                        "type": notif.type,
+                        "created_at": notif.created_at.isoformat(),
+                    },
+                })