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/models/__init__.py

@@ -6,5 +6,6 @@ from app.models.context_file import ContextFile
 from app.models.skill import Skill
 from app.models.document import Document
 from app.models.memory_entry import MemoryEntry
+from app.models.notification import Notification
 
-__all__ = ["User", "Session", "Chat", "Message", "ContextFile", "Skill", "Document", "MemoryEntry"]
+__all__ = ["User", "Session", "Chat", "Message", "ContextFile", "Skill", "Document", "MemoryEntry", "Notification"]

backend/app/models/notification.py

@@ -0,0 +1,27 @@
+import uuid
+from datetime import datetime
+
+from sqlalchemy import DateTime, ForeignKey, String, Text
+from sqlalchemy.dialects.postgresql import JSONB, UUID
+from sqlalchemy.orm import Mapped, mapped_column, relationship
+
+from app.database import Base
+
+
+class Notification(Base):
+    __tablename__ = "notifications"
+
+    user_id: Mapped[uuid.UUID] = mapped_column(
+        UUID(as_uuid=True), ForeignKey("users.id", ondelete="CASCADE"), nullable=False, index=True
+    )
+    title: Mapped[str] = mapped_column(String(255), nullable=False)
+    body: Mapped[str] = mapped_column(Text, nullable=False)
+    type: Mapped[str] = mapped_column(String(30), nullable=False, default="info")
+    channel: Mapped[str] = mapped_column(String(20), nullable=False, default="in_app")
+    status: Mapped[str] = mapped_column(String(20), nullable=False, default="pending")
+    scheduled_at: Mapped[datetime | None] = mapped_column(DateTime(timezone=True), nullable=True)
+    sent_at: Mapped[datetime | None] = mapped_column(DateTime(timezone=True), nullable=True)
+    read_at: Mapped[datetime | None] = mapped_column(DateTime(timezone=True), nullable=True)
+    metadata_: Mapped[dict | None] = mapped_column("metadata", JSONB, nullable=True)
+
+    user: Mapped["User"] = relationship(back_populates="notifications")  # noqa: F821

backend/app/models/user.py

@@ -29,3 +29,4 @@ class User(Base):
     skills: Mapped[list["Skill"]] = relationship(back_populates="user", cascade="all, delete-orphan")  # noqa: F821
     documents: Mapped[list["Document"]] = relationship(back_populates="user", cascade="all, delete-orphan")  # noqa: F821
     memory_entries: Mapped[list["MemoryEntry"]] = relationship(back_populates="user", cascade="all, delete-orphan")  # noqa: F821
+    notifications: Mapped[list["Notification"]] = relationship(back_populates="user", cascade="all, delete-orphan")  # noqa: F821