Add supplements, kettlebell, calendar, push notifications, and PWA support

- Supplement tracking: CRUD endpoints, /today, /logs, Supplements page
- Kettlebell workouts: session tracking, analytics endpoint, ActiveSession page
- Calendar module: events CRUD, calendar components
- Push notifications: VAPID keys, PushSubscription model, APScheduler reminders,
  service worker with push/notificationclick handlers, Profile notifications UI
- PWA: vite-plugin-pwa, manifest, icons, service worker generation
- Frontend: TypeScript types, API modules, ConfirmModal, toast notifications
- Auth fixes: password hashing, nutrition endpoint auth
- CLAUDE.md: project documentation and development guide

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

backend/app/models/supplement.py

@@ -0,0 +1,27 @@
+from datetime import datetime
+from typing import List, Optional
+
+from sqlalchemy import Column
+from sqlmodel import JSON, Field, SQLModel
+
+
+class Supplement(SQLModel, table=True):
+    id: Optional[int] = Field(default=None, primary_key=True)
+    user_id: int = Field(foreign_key="user.id", index=True)
+    name: str = Field(index=True)
+    dosage: float
+    unit: str  # mg / mcg / IU / g
+    frequency: str = Field(default="daily")  # daily / weekly / as_needed
+    scheduled_times: List[str] = Field(default=[], sa_column=Column(JSON))  # ["08:00", "20:00"]
+    notes: Optional[str] = None
+    is_active: bool = Field(default=True)
+    created_at: datetime = Field(default_factory=datetime.utcnow)
+
+
+class SupplementLog(SQLModel, table=True):
+    id: Optional[int] = Field(default=None, primary_key=True)
+    user_id: int = Field(foreign_key="user.id", index=True)
+    supplement_id: int = Field(foreign_key="supplement.id", index=True)
+    taken_at: datetime = Field(default_factory=datetime.utcnow)
+    dose_taken: Optional[float] = None
+    notes: Optional[str] = None