feat: add appointments, campaigns, admin, storage, tests and various updates

- Add new routers: admin, appointments, campaigns
- Add storage service and logging config
- Add migrations directory and test suite with pytest config
- Add supabase_migration_features.sql
- Update models, dependencies, config, and existing routers
- Remove whatsapp_service (deleted)
- Update pyproject.toml and uv.lock dependencies

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

app/routers/billing.py

@@ -89,6 +89,17 @@ async def stripe_webhook(
 
         supabase = get_supabase()
         event_type = event.get("type", "")
+        event_id = event.get("id", "")
+
+        # Idempotency check: skip already-processed events
+        if event_id:
+            existing = supabase.table("stripe_webhook_events") \
+                .select("stripe_event_id") \
+                .eq("stripe_event_id", event_id) \
+                .execute()
+            if existing.data:
+                logger.info(f"Stripe event {event_id} already processed, skipping")
+                return {"received": True}
 
         if event_type == "checkout.session.completed":
             session = event["data"]["object"]
@@ -140,6 +151,16 @@ async def stripe_webhook(
                         except Exception as e:
                             logger.warning(f"Failed to send cancellation notification: {e}")
 
+        # Record event as processed
+        if event_id:
+            try:
+                supabase.table("stripe_webhook_events").insert({
+                    "stripe_event_id": event_id,
+                    "event_type": event_type,
+                }).execute()
+            except Exception as e:
+                logger.warning(f"Failed to record stripe event {event_id}: {e}")
+
         return {"received": True}
 
     except HTTPException: