feat(loyalty): inline edit for transaction categories in admin

Category list now has a pencil edit button that expands inline with
name + FR/DE/LB translation fields. Save updates via PATCH API.
View mode shows translations summary next to the name.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

app/modules/loyalty/static/admin/js/loyalty-merchant-detail.js

@@ -39,6 +39,8 @@ function adminLoyaltyMerchantDetail() {
         showAddCategory: false,
         newCategoryName: '',
         newCategoryTranslations: { fr: '', de: '', lb: '' },
+        editingCategoryId: null,
+        editCategoryData: { name: '', translations: { fr: '', de: '', lb: '' } },
 
         // State
         loading: false,
@@ -307,6 +309,38 @@ function adminLoyaltyMerchantDetail() {
             }
         },
 
+        startEditCategory(cat) {
+            this.editingCategoryId = cat.id;
+            this.editCategoryData = {
+                name: cat.name,
+                translations: {
+                    fr: cat.name_translations?.fr || '',
+                    de: cat.name_translations?.de || '',
+                    lb: cat.name_translations?.lb || '',
+                },
+            };
+        },
+
+        async saveEditCategory(catId) {
+            if (!this.editCategoryData.name) return;
+            try {
+                const translations = { en: this.editCategoryData.name };
+                for (const [lang, val] of Object.entries(this.editCategoryData.translations)) {
+                    if (val) translations[lang] = val;
+                }
+
+                await apiClient.patch(`/admin/loyalty/stores/${this.selectedCategoryStoreId}/categories/${catId}`, {
+                    name: this.editCategoryData.name,
+                    name_translations: Object.keys(translations).length > 0 ? translations : null,
+                });
+                this.editingCategoryId = null;
+                await this.loadCategoriesForStore();
+                Utils.showToast('Category updated', 'success');
+            } catch (error) {
+                Utils.showToast(error.message || 'Failed to update category', 'error');
+            }
+        },
+
         async toggleCategoryActive(cat) {
             try {
                 await apiClient.patch(`/admin/loyalty/stores/${this.selectedCategoryStoreId}/categories/${cat.id}`, {