major refactoring adding vendor and customer features

tests/conftest.py

@@ -12,7 +12,7 @@ from models.database.marketplace_import_job import MarketplaceImportJob
 from models.database.marketplace_product import MarketplaceProduct
 from models.database.vendor import Vendor
 from models.database.product import Product
-from models.database.stock import Stock
+from models.database.inventory import Inventory
 from models.database.user import User
 
 # Use in-memory SQLite database for tests
@@ -90,6 +90,7 @@ pytest_plugins = [
     "tests.fixtures.auth_fixtures",
     "tests.fixtures.marketplace_product_fixtures",
     "tests.fixtures.vendor_fixtures",
+    "tests.fixtures.customer_fixtures",
     "tests.fixtures.marketplace_import_job_fixtures",
     "tests.fixtures.testing_fixtures",
 ]