fix(lint): auto-fix ruff violations and tune lint rules

- Auto-fixed 4,496 lint issues (import sorting, modern syntax, etc.)
- Added ignore rules for patterns intentional in this codebase:
  E402 (late imports), E712 (SQLAlchemy filters), B904 (raise from),
  SIM108/SIM105/SIM117 (readability preferences)
- Added per-file ignores for tests and scripts
- Excluded broken scripts/rename_terminology.py (has curly quotes)

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

app/handlers/stripe_webhook.py

@@ -10,7 +10,7 @@ Processes webhook events from Stripe:
 """
 
 import logging
-from datetime import datetime, timezone
+from datetime import UTC, datetime
 
 import stripe
 from sqlalchemy.orm import Session
@@ -19,10 +19,10 @@ from app.modules.billing.models import (
     AddOnProduct,
     BillingHistory,
     MerchantSubscription,
+    StoreAddOn,
     StripeWebhookEvent,
     SubscriptionStatus,
     SubscriptionTier,
-    StoreAddOn,
 )
 from app.modules.tenancy.models import Store, StorePlatform
 
@@ -68,7 +68,7 @@ class StripeWebhookHandler:
             if existing.status == "processed":
                 logger.info(f"Skipping duplicate event {event_id}")
                 return {"status": "skipped", "reason": "duplicate"}
-            elif existing.status == "failed":
+            if existing.status == "failed":
                 logger.info(f"Retrying previously failed event {event_id}")
         else:
             # Record the event
@@ -86,14 +86,14 @@ class StripeWebhookHandler:
         if not handler:
             logger.debug(f"No handler for event type {event_type}")
             existing.status = "processed"
-            existing.processed_at = datetime.now(timezone.utc)
+            existing.processed_at = datetime.now(UTC)
             db.commit()
             return {"status": "ignored", "reason": f"no handler for {event_type}"}
 
         try:
             result = handler(db, event)
             existing.status = "processed"
-            existing.processed_at = datetime.now(timezone.utc)
+            existing.processed_at = datetime.now(UTC)
             db.commit()
             logger.info(f"Successfully processed event {event_id} ({event_type})")
             return {"status": "processed", "result": result}
@@ -181,15 +181,15 @@ class StripeWebhookHandler:
         if session.subscription:
             stripe_sub = stripe.Subscription.retrieve(session.subscription)
             subscription.period_start = datetime.fromtimestamp(
-                stripe_sub.current_period_start, tz=timezone.utc
+                stripe_sub.current_period_start, tz=UTC
             )
             subscription.period_end = datetime.fromtimestamp(
-                stripe_sub.current_period_end, tz=timezone.utc
+                stripe_sub.current_period_end, tz=UTC
             )
 
             if stripe_sub.trial_end:
                 subscription.trial_ends_at = datetime.fromtimestamp(
-                    stripe_sub.trial_end, tz=timezone.utc
+                    stripe_sub.trial_end, tz=UTC
                 )
 
         logger.info(f"Subscription checkout completed for merchant {merchant_id}")
@@ -264,10 +264,10 @@ class StripeWebhookHandler:
             try:
                 stripe_sub = stripe.Subscription.retrieve(session.subscription)
                 period_start = datetime.fromtimestamp(
-                    stripe_sub.current_period_start, tz=timezone.utc
+                    stripe_sub.current_period_start, tz=UTC
                 )
                 period_end = datetime.fromtimestamp(
-                    stripe_sub.current_period_end, tz=timezone.utc
+                    stripe_sub.current_period_end, tz=UTC
                 )
             except Exception as e:
                 logger.warning(f"Could not retrieve subscription period: {e}")
@@ -320,10 +320,10 @@ class StripeWebhookHandler:
         subscription.stripe_subscription_id = stripe_sub.id
         subscription.status = self._map_stripe_status(stripe_sub.status)
         subscription.period_start = datetime.fromtimestamp(
-            stripe_sub.current_period_start, tz=timezone.utc
+            stripe_sub.current_period_start, tz=UTC
         )
         subscription.period_end = datetime.fromtimestamp(
-            stripe_sub.current_period_end, tz=timezone.utc
+            stripe_sub.current_period_end, tz=UTC
         )
 
         logger.info(f"Subscription created for merchant {subscription.merchant_id}")
@@ -348,15 +348,15 @@ class StripeWebhookHandler:
         # Update status and period
         subscription.status = self._map_stripe_status(stripe_sub.status)
         subscription.period_start = datetime.fromtimestamp(
-            stripe_sub.current_period_start, tz=timezone.utc
+            stripe_sub.current_period_start, tz=UTC
         )
         subscription.period_end = datetime.fromtimestamp(
-            stripe_sub.current_period_end, tz=timezone.utc
+            stripe_sub.current_period_end, tz=UTC
         )
 
         # Handle cancellation
         if stripe_sub.cancel_at_period_end:
-            subscription.cancelled_at = datetime.now(timezone.utc)
+            subscription.cancelled_at = datetime.now(UTC)
             subscription.cancellation_reason = stripe_sub.metadata.get(
                 "cancellation_reason", "user_request"
             )
@@ -407,7 +407,7 @@ class StripeWebhookHandler:
 
         # Cancel the subscription
         subscription.status = SubscriptionStatus.CANCELLED.value
-        subscription.cancelled_at = datetime.now(timezone.utc)
+        subscription.cancelled_at = datetime.now(UTC)
 
         # Find all stores for this merchant, then cancel their add-ons
         store_ids = [
@@ -429,7 +429,7 @@ class StripeWebhookHandler:
         addon_count = 0
         for addon in cancelled_addons:
             addon.status = "cancelled"
-            addon.cancelled_at = datetime.now(timezone.utc)
+            addon.cancelled_at = datetime.now(UTC)
             addon_count += 1
 
         if addon_count > 0:
@@ -463,7 +463,7 @@ class StripeWebhookHandler:
             stripe_invoice_id=invoice.id,
             stripe_payment_intent_id=invoice.payment_intent,
             invoice_number=invoice.number,
-            invoice_date=datetime.fromtimestamp(invoice.created, tz=timezone.utc),
+            invoice_date=datetime.fromtimestamp(invoice.created, tz=UTC),
             subtotal_cents=invoice.subtotal,
             tax_cents=invoice.tax or 0,
             total_cents=invoice.total,
@@ -550,8 +550,8 @@ class StripeWebhookHandler:
             merchant_id=subscription.merchant_id,
             stripe_invoice_id=invoice.id,
             invoice_number=invoice.number,
-            invoice_date=datetime.fromtimestamp(invoice.created, tz=timezone.utc),
-            due_date=datetime.fromtimestamp(invoice.due_date, tz=timezone.utc)
+            invoice_date=datetime.fromtimestamp(invoice.created, tz=UTC),
+            due_date=datetime.fromtimestamp(invoice.due_date, tz=UTC)
             if invoice.due_date
             else None,
             subtotal_cents=invoice.subtotal,