fix(billing): handle customer.subscription.created webhook + test isolation

- Add customer.subscription.created → subscription.activated mapping in
  stripe.parse_webhook so direct API subscription creation also creates DB rows
- Add customer.subscription.created to setup_stripe.py enabled_events
- Pin PAYMENT_PROVIDER=paddle and STRIPE_WEBHOOK_SECRET="" in test conftest
  so billing tests don't hit real Stripe API when env has Stripe keys
- Add 8 unit tests for stripe.parse_webhook covering all event types

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

web/src/padelnomics/billing/stripe.py

@@ -152,6 +152,7 @@ def parse_webhook(payload: bytes) -> dict:
 
     Maps Stripe event types to the shared format used by _handle_webhook_event():
     - checkout.session.completed (mode=subscription) → subscription.activated
+    - customer.subscription.created → subscription.activated
     - customer.subscription.updated → subscription.updated
     - customer.subscription.deleted → subscription.canceled
     - invoice.payment_failed → subscription.past_due
@@ -218,6 +219,23 @@ def parse_webhook(payload: bytes) -> dict:
                 "custom_data": metadata,
             }
 
+    elif stripe_type == "customer.subscription.created":
+        # New subscription — map to subscription.activated so the handler creates the DB row
+        status = _map_stripe_status(obj.get("status", ""))
+        return {
+            "event_type": "subscription.activated",
+            "subscription_id": obj.get("id", ""),
+            "customer_id": str(customer_id),
+            "user_id": user_id,
+            "supplier_id": supplier_id,
+            "plan": plan,
+            "status": status,
+            "current_period_end": _unix_to_iso(obj.get("current_period_end")),
+            "data": obj,
+            "items": _extract_sub_items(obj),
+            "custom_data": metadata,
+        }
+
     elif stripe_type == "customer.subscription.updated":
         status = _map_stripe_status(obj.get("status", ""))
         return {

web/src/padelnomics/scripts/setup_stripe.py

@@ -189,6 +189,7 @@ def create(conn):
     webhook_url = f"{BASE_URL}/billing/webhook/stripe"
     enabled_events = [
         "checkout.session.completed",
+        "customer.subscription.created",
         "customer.subscription.updated",
         "customer.subscription.deleted",
         "invoice.payment_failed",