feat(arch): add API-007 rule to enforce layered architecture

Add architecture rule that detects when API routes import database
models directly, enforcing Routes → Services → Models pattern.

Changes:
- Add API-007 rule to .architecture-rules/api.yaml
- Add _check_no_model_imports() validation to validator script
- Update customer imports to use canonical module location
- Add storefront module restructure implementation plan

The validator now detects 81 violations across 67 API files where
database models are imported directly instead of going through
services. This is Phase 1 of the storefront restructure plan.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

tests/unit/services/test_admin_customer_service.py

@@ -9,7 +9,7 @@ import pytest
 
 from app.exceptions.customer import CustomerNotFoundException
 from app.services.admin_customer_service import AdminCustomerService
-from models.database.customer import Customer
+from app.modules.customers.models.customer import Customer
 
 
 @pytest.fixture

tests/unit/services/test_customer_address_service.py

@@ -7,7 +7,7 @@ import pytest
 
 from app.exceptions import AddressLimitExceededException, AddressNotFoundException
 from app.services.customer_address_service import CustomerAddressService
-from models.database.customer import CustomerAddress
+from app.modules.customers.models.customer import CustomerAddress
 from models.schema.customer import CustomerAddressCreate, CustomerAddressUpdate
 
 

tests/unit/services/test_order_service.py

@@ -27,7 +27,7 @@ from app.services.order_service import (
     OrderService,
     order_service,
 )
-from models.database.customer import Customer
+from app.modules.customers.models.customer import Customer
 from models.database.order import Order, OrderItem