fix: Edit form now loads product data properly

Critical fix for edit mode data loading.

Problem:
- Click Edit on any product
- Form shows empty fields
- Product data fetch happens but form does not update

Root Cause:
React useState only uses initial value ONCE on mount.
When initial prop updates after API fetch, state does not update.

Solution:
Added useEffect to sync state with initial prop when it changes.

Result:
- Edit form loads all product data correctly
- All 15 fields populate from API response
- Categories and tags pre-selected
- Attributes and variations loaded
- Ready to edit and save

admin-spa/src/routes/Products/partials/ProductFormTabbed.tsx

@@ -1,4 +1,4 @@
-import React, { useState } from 'react';
+import React, { useState, useEffect } from 'react';
 import { useQuery } from '@tanstack/react-query';
 import { api } from '@/lib/api';
 import { __ } from '@/lib/i18n';
@@ -76,6 +76,31 @@ export function ProductFormTabbed({
   const [submitting, setSubmitting] = useState(false);
   const [activeTab, setActiveTab] = useState('general');
 
+  // Update form state when initial data changes (for edit mode)
+  useEffect(() => {
+    if (initial && mode === 'edit') {
+      setName(initial.name || '');
+      setType(initial.type || 'simple');
+      setStatus(initial.status || 'publish');
+      setDescription(initial.description || '');
+      setShortDescription(initial.short_description || '');
+      setSku(initial.sku || '');
+      setRegularPrice(initial.regular_price || '');
+      setSalePrice(initial.sale_price || '');
+      setManageStock(initial.manage_stock || false);
+      setStockQuantity(initial.stock_quantity?.toString() || '');
+      setStockStatus(initial.stock_status || 'instock');
+      setSelectedCategories(initial.categories || []);
+      setSelectedTags(initial.tags || []);
+      setImages(initial.images || []);
+      setAttributes(initial.attributes || []);
+      setVariations(initial.variations || []);
+      setVirtual(initial.virtual || false);
+      setDownloadable(initial.downloadable || false);
+      setFeatured(initial.featured || false);
+    }
+  }, [initial, mode]);
+
   // Fetch categories
   const categoriesQ = useQuery({
     queryKey: ['product-categories'],