feat(validators): add noqa suppression support to security and performance validators

- Add centralized _is_noqa_suppressed() to BaseValidator with normalization
  (accepts both SEC001 and SEC-001 formats for ruff compatibility)
- Wire noqa support into all 21 security and 18 performance check functions
- Add ruff external config for SEC/PERF/MOD/EXC codes in pyproject.toml
- Convert all 280 Python noqa comments to dashless format (ruff-compatible)
- Add site/ to IGNORE_PATTERNS (excludes mkdocs build output)
- Suppress 152 false positive findings (test passwords, seed data, validator
  self-references, Apple Wallet SHA1, etc.)
- Security: 79 errors → 0, 60 warnings → 0
- Performance: 80 warnings → 77 (3 test script suppressions)
- Add proposal doc with noqa inventory and remaining findings recommendations

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

app/modules/billing/exceptions.py

@@ -90,7 +90,7 @@ class SubscriptionNotCancelledException(BusinessLogicException):
         )
 
 
-class SubscriptionAlreadyCancelledException(BusinessLogicException):  # noqa: MOD-025
+class SubscriptionAlreadyCancelledException(BusinessLogicException):  # noqa: MOD025
     """Raised when trying to cancel an already cancelled subscription."""
 
     def __init__(self):
@@ -170,7 +170,7 @@ class StripePriceNotConfiguredException(BusinessLogicException):
         self.tier_code = tier_code
 
 
-class PaymentFailedException(BillingException):  # noqa: MOD-025
+class PaymentFailedException(BillingException):  # noqa: MOD025
     """Raised when a payment fails."""
 
     def __init__(self, message: str, stripe_error: str | None = None):

app/modules/billing/services/billing_service.py

@@ -542,7 +542,7 @@ class BillingService:
         if stripe_service.is_configured and store_addon.stripe_subscription_item_id:
             try:
                 stripe_service.cancel_subscription_item(store_addon.stripe_subscription_item_id)
-            except Exception as e:  # noqa: EXC-003
+            except Exception as e:  # noqa: EXC003
                 logger.warning(f"Failed to cancel addon in Stripe: {e}")
 
         # Mark as cancelled

app/modules/billing/tests/unit/test_billing_service.py

@@ -488,7 +488,7 @@ class TestBillingServiceCheckout:
 
             with pytest.raises(PaymentSystemNotConfiguredException):
                 self.service.create_checkout_session(
-                    db, 1, 1, "essential", False, "http://ok", "http://cancel"
+                    db, 1, 1, "essential", False, "http://ok", "http://cancel"  # noqa: SEC034
                 )
 
     def test_checkout_nonexistent_tier_raises(self, db):
@@ -500,7 +500,7 @@ class TestBillingServiceCheckout:
 
             with pytest.raises(TierNotFoundException):
                 self.service.create_checkout_session(
-                    db, 1, 1, "nonexistent", False, "http://ok", "http://cancel"
+                    db, 1, 1, "nonexistent", False, "http://ok", "http://cancel"  # noqa: SEC034
                 )
 
 
@@ -525,7 +525,7 @@ class TestBillingServicePortal:
             mock_stripe.is_configured = False
 
             with pytest.raises(PaymentSystemNotConfiguredException):
-                self.service.create_portal_session(db, 1, 1, "http://return")
+                self.service.create_portal_session(db, 1, 1, "http://return")  # noqa: SEC034
 
     def test_portal_no_subscription_raises(self, db):
         """Raises NoActiveSubscriptionException when no subscription found."""
@@ -535,7 +535,7 @@ class TestBillingServicePortal:
             mock_stripe.is_configured = True
 
             with pytest.raises(NoActiveSubscriptionException):
-                self.service.create_portal_session(db, 99999, 99999, "http://return")
+                self.service.create_portal_session(db, 99999, 99999, "http://return")  # noqa: SEC034
 
     def test_portal_no_customer_id_raises(self, db, bs_subscription):
         """Raises when subscription has no stripe_customer_id."""
@@ -549,7 +549,7 @@ class TestBillingServicePortal:
                     db,
                     bs_subscription.merchant_id,
                     bs_subscription.platform_id,
-                    "http://return",
+                    "http://return",  # noqa: SEC034
                 )