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/ai/kettlebell.py

@@ -0,0 +1,57 @@
+import dspy
+from pydantic import BaseModel, Field
+
+
+class ExerciseBlock(BaseModel):
+    order: int = Field(description="Position in workout sequence")
+    name: str = Field(description="Exercise name")
+    description: str = Field(description="Brief description of the movement")
+    sets: int = Field(description="Number of sets")
+    reps: int = Field(description="Number of reps per set (0 if timed)")
+    duration_seconds: int = Field(description="Duration in seconds per set (0 if rep-based)")
+    weight_kg: float = Field(description="Prescribed weight in kg")
+    rest_seconds: int = Field(description="Rest time between sets in seconds")
+    coaching_tip: str = Field(description="Key coaching cue for this exercise")
+
+
+class KettlebellSessionOutput(BaseModel):
+    reasoning: str = Field(description="Step-by-step reasoning for session design choices")
+    title: str = Field(description="Session title")
+    focus: str = Field(description="Session focus e.g. strength, conditioning, mobility")
+    total_duration_min: int = Field(description="Estimated total workout duration in minutes")
+    difficulty: str = Field(description="Difficulty level: beginner, intermediate, advanced")
+    exercises: list[ExerciseBlock] = Field(description="Ordered list of exercises in the session")
+    notes: str = Field(description="Coaching notes and any special instructions for the session")
+
+
+class GenerateKettlebellSession(dspy.Signature):
+    """Generate a personalized kettlebell workout session based on user profile and preferences.
+
+    Think step-by-step: assess user fitness level, pick movements appropriate to the focus and
+    difficulty, assign weights respecting progressive overload principles from available weights,
+    sequence exercises for proper warm-up and fatigue management, and ensure total work time
+    (sets × reps/duration + rest periods) fits within the requested duration.
+    """
+
+    user_profile: str = dspy.InputField(desc="User details including age, weight, fitness level, and goals")
+    available_weights_kg: str = dspy.InputField(desc="Comma-separated list of available kettlebell weights in kg")
+    focus: str = dspy.InputField(desc="Session focus: strength, conditioning, mobility, fat loss, etc.")
+    duration_minutes: int = dspy.InputField(desc="Target session duration in minutes")
+    session: KettlebellSessionOutput = dspy.OutputField(desc="Complete structured kettlebell session")
+
+
+class KettlebellModule(dspy.Module):
+    def __init__(self):
+        super().__init__()
+        self.generate = dspy.ChainOfThought(GenerateKettlebellSession)
+
+    def forward(self, user_profile: str, available_weights_kg: str, focus: str, duration_minutes: int):
+        return self.generate(
+            user_profile=user_profile,
+            available_weights_kg=available_weights_kg,
+            focus=focus,
+            duration_minutes=duration_minutes,
+        )
+
+
+kettlebell_module = KettlebellModule()