refactor: migrate models to canonical module locations

- Move Product/ProductTranslation to app/modules/catalog/models/
- Move VendorOnboarding to app/modules/marketplace/models/
- Delete legacy re-export files for marketplace models:
  - letzshop.py, marketplace.py, marketplace_product.py
  - marketplace_product_translation.py, marketplace_import_job.py
- Delete legacy product.py, product_translation.py, onboarding.py
- Update all imports across services, tasks, tests to use module locations

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

scripts/debug_historical_import.py

@@ -6,7 +6,7 @@ sys.path.insert(0, ".")
 
 from app.core.database import SessionLocal
 from app.services.letzshop.credentials_service import LetzshopCredentialsService
-from models.database.letzshop import LetzshopHistoricalImportJob
+from app.modules.marketplace.models import LetzshopHistoricalImportJob
 
 
 def get_valid_shipment_states(vendor_id: int = 1):

scripts/seed_demo.py

@@ -55,13 +55,13 @@ from app.modules.cms.models import ContentPage
 from models.database.admin import PlatformAlert
 from models.database.company import Company
 from app.modules.customers.models.customer import Customer, CustomerAddress
-from models.database.marketplace_import_job import MarketplaceImportJob
-from models.database.marketplace_product import MarketplaceProduct
-from models.database.marketplace_product_translation import (
+from app.modules.marketplace.models import (
+    MarketplaceImportJob,
+    MarketplaceProduct,
     MarketplaceProductTranslation,
 )
 from app.modules.orders.models import Order, OrderItem
-from models.database.product import Product
+from app.modules.catalog.models import Product
 from models.database.user import User
 from models.database.vendor import Role, Vendor, VendorUser
 from models.database.vendor_domain import VendorDomain

scripts/verify_setup.py

@@ -144,9 +144,8 @@ def verify_model_structure():
 
         # Import specific models
         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.product import Product
+        from app.modules.marketplace.models import MarketplaceImportJob, MarketplaceProduct
+        from app.modules.catalog.models import Product
         from models.database.user import User
         from models.database.vendor import Vendor