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/analytics/services/stats_service.py

@@ -20,10 +20,10 @@ from sqlalchemy.orm import Session
 
 from app.exceptions import AdminOperationException, VendorNotFoundException
 from app.modules.customers.models.customer import Customer
-from models.database.inventory import Inventory
+from app.modules.inventory.models import Inventory
 from models.database.marketplace_import_job import MarketplaceImportJob
 from models.database.marketplace_product import MarketplaceProduct
-from models.database.order import Order
+from app.modules.orders.models import Order
 from models.database.product import Product
 from models.database.user import User
 from models.database.vendor import Vendor