refactor: update module imports to use module locations

Update all module files to import from canonical module locations
instead of legacy re-export files:
- checkout, orders, customers routes: use module schemas
- catalog, marketplace schemas: use inventory module schemas
- marketplace, customers, inventory, analytics services: use module models

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

app/modules/checkout/routes/api/storefront.py

@@ -31,7 +31,7 @@ from app.modules.orders.services import order_service
 from app.services.email_service import EmailService
 from middleware.vendor_context import require_vendor_context
 from models.database.vendor import Vendor
-from models.schema.order import OrderCreate, OrderResponse
+from app.modules.orders.schemas import OrderCreate, OrderResponse
 
 router = APIRouter()
 logger = logging.getLogger(__name__)