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>

tests/unit/models/database/test_product.py

@@ -251,6 +251,8 @@ class TestProductInventoryProperties:
         inv1 = Inventory(
             product_id=product.id,
             vendor_id=test_vendor.id,
+            warehouse="strassen",
+            bin_location="SA-01-01",
             location="WAREHOUSE_A",
             quantity=100,
             reserved_quantity=10,
@@ -258,6 +260,8 @@ class TestProductInventoryProperties:
         inv2 = Inventory(
             product_id=product.id,
             vendor_id=test_vendor.id,
+            warehouse="strassen",
+            bin_location="SA-01-02",
             location="WAREHOUSE_B",
             quantity=50,
             reserved_quantity=5,
@@ -311,6 +315,8 @@ class TestProductInventoryProperties:
         inv = Inventory(
             product_id=product.id,
             vendor_id=test_vendor.id,
+            warehouse="strassen",
+            bin_location="DIG-01-01",
             location="DIGITAL_LICENSES",
             quantity=10,
             reserved_quantity=2,