Fix: Display variant price and stock directly in Product Edit page

**Problem:**
- Variant price overrides and stock quantities were hidden in collapsible
  panels in the Product Edit page
- The Edit page was showing the VariantCollections system (VariantsJson)
  instead of the actual ProductVariant records created by text import
- User had to expand each variant panel to see price and stock values

**Solution:**
1. **ProductsController.cs (Lines 101-103):**
   - Added call to GetProductVariantsAsync() to load actual variant records
   - Added ViewData["ProductVariants"] to pass data to view

2. **Edit.cshtml (Lines 320-413):**
   - Added new collapsible section "Product Variants"
   - Displays variants in a table with directly visible columns:
     * Name, Type, Price, Stock Level, Sort Order, Status
   - No hidden panels - all information visible at a glance
   - Added quick summary with total variants, stock, and price range
   - Includes helpful links to ProductVariants management page

**Technical Details:**
- Price displays in green with £ symbol when override exists
- Stock shows color-coded badges (green=in stock, red=out of stock)
- Section only appears if variants exist (conditional rendering)
- Expanded by default (aria-expanded="true") for immediate visibility

**Impact:**
- User can now see all variant prices and stock quantities immediately
- No need to click/expand individual variant panels
- Better UX for products imported via text import format
- Maintains separation between VariantCollections system and ProductVariants

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

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

LittleShop/Areas/Admin/Controllers/ProductsController.cs

@@ -98,6 +98,10 @@ public class ProductsController : Controller
         var productMultiBuys = await _productService.GetProductMultiBuysAsync(id);
         ViewData["ProductMultiBuys"] = productMultiBuys;
 
+        // Load product variants
+        var productVariants = await _productService.GetProductVariantsAsync(id);
+        ViewData["ProductVariants"] = productVariants;
+
         // TODO: Add ReviewService injection and retrieve actual reviews
         // For now, providing mock review data for demonstration
         ViewData["ProductReviews"] = new[]