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/catalog/schemas/catalog.py

@@ -10,7 +10,7 @@ from datetime import datetime
 
 from pydantic import BaseModel, ConfigDict, Field
 
-from models.schema.inventory import InventoryLocationResponse
+from app.modules.inventory.schemas import InventoryLocationResponse
 from models.schema.marketplace_product import MarketplaceProductResponse