Debug: Add logging to variant import for troubleshooting

Added detailed logging to ParseAndImportVariantLine to output:
- Variant name/value
- Price override
- Stock quantity
- Variant type

This will help diagnose why variant price and stock aren't showing up

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

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

LittleShop/Services/ProductImportService.cs

@@ -683,6 +683,10 @@ public class ProductImportService : IProductImportService
             VariantType = variantType
         };
 
+        _logger.LogInformation(
+            "Creating variant: Name={Name}, Price={Price}, Stock={Stock}, Type={Type}",
+            variantValue, priceOverride, stockQuantity, variantType);
+
         await _productService.CreateProductVariantAsync(variantDto);
     }
 

blank.csv

@@ -0,0 +1 @@
+Name,Description,Price,Weight,WeightUnit,StockQuantity,CategoryName,IsActive,Variations,PhotoUrls