fix: PHP Fatal Error and attribute input UX

Critical Fixes:

1. ✅ PHP Fatal Error - FIXED
   Problem: call_user_func() error - Permissions::check_admin does not exist
   Cause: Method name mismatch in ProductsController.php
   Solution: Changed all 8 occurrences from:
     'permission_callback' => [Permissions::class, 'check_admin']
   To:
     'permission_callback' => [Permissions::class, 'check_admin_permission']

   Affected routes:
   - GET /products
   - GET /products/:id
   - POST /products
   - PUT /products/:id
   - DELETE /products/:id
   - GET /products/categories
   - GET /products/tags
   - GET /products/attributes

2. ✅ Attribute Options Input - FIXED
   Problem: Cannot type anything after first word (cursor jumps)
   Cause: Controlled input with immediate state update on onChange
   Solution: Changed to uncontrolled input with onBlur

   Changes:
   - value → defaultValue (uncontrolled)
   - onChange → onBlur (update on blur)
   - Added key prop for proper re-rendering
   - Added onKeyDown for Enter key support
   - Updated help text: "press Enter or click away"

   Now you can:
   ✅ Type: Red, Blue, Green (naturally!)
   ✅ Type: Red | Blue | Green (pipe works too!)
   ✅ Press Enter to save
   ✅ Click away to save
   ✅ No cursor jumping!

Result:
- Products index page loads without PHP error
- Attribute options input works naturally
- Both comma and pipe separators supported

admin-spa/src/routes/Products/partials/tabs/VariationsTab.tsx

@@ -136,8 +136,9 @@ export function VariationsTab({
                   <div>
                     <Label>{__('Options')}</Label>
                     <Input
-                      value={attr.options.join(', ')}
-                      onChange={(e) => {
+                      key={`options-${index}-${attr.options.length}`}
+                      defaultValue={attr.options.join(', ')}
+                      onBlur={(e) => {
                         const input = e.target.value;
                         // Split by comma or pipe, trim whitespace
                         const options = input
@@ -146,11 +147,17 @@ export function VariationsTab({
                           .filter(Boolean);
                         updateAttribute(index, 'options', options);
                       }}
+                      onKeyDown={(e) => {
+                        // Update on Enter key
+                        if (e.key === 'Enter') {
+                          e.currentTarget.blur();
+                        }
+                      }}
                       placeholder={__('Red, Blue, Green (comma or pipe separated)')}
                       className="mt-1.5"
                     />
                     <p className="text-xs text-muted-foreground mt-1">
-                      {__('Type naturally: Red, Blue, Green (comma or | works)')}
+                      {__('Type naturally: Red, Blue, Green (press Enter or click away)')}
                     </p>
                   </div>
                 </div>