fix: add bin_location to inventory fixtures and service

- Add warehouse and bin_location fields to test fixtures
- Update InventoryService to include warehouse/bin_location when creating entries
- Fix all Inventory model instantiations in tests to include required fields
- All 119 inventory tests now pass

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

app/services/inventory_service.py

@@ -84,7 +84,9 @@ class InventoryService:
             new_inventory = Inventory(
                 product_id=inventory_data.product_id,
                 vendor_id=vendor_id,
-                location=location,
+                warehouse="strassen",  # Default warehouse
+                bin_location=location,  # Use location as bin location
+                location=location,  # Keep for backward compatibility
                 quantity=inventory_data.quantity,
                 gtin=product.marketplace_product.gtin,  # Optional reference
             )
@@ -148,7 +150,9 @@ class InventoryService:
                 new_inventory = Inventory(
                     product_id=inventory_data.product_id,
                     vendor_id=vendor_id,
-                    location=location,
+                    warehouse="strassen",  # Default warehouse
+                    bin_location=location,  # Use location as bin location
+                    location=location,  # Keep for backward compatibility
                     quantity=inventory_data.quantity,
                     gtin=product.marketplace_product.gtin,
                 )