feat(loyalty): transaction categories — admin UI + web terminal

Admin merchant detail page:
- New "Transaction Categories" section with store selector
- Inline add form, activate/deactivate toggle, delete button
- Categories CRUD via /admin/loyalty/stores/{id}/categories API

Web terminal:
- Loads categories on init via /store/loyalty/categories
- Category pill selector shown in PIN modal before stamp/earn actions
- Selected category_id passed to stamp and points API calls
- Categories are optional (selector hidden when none configured)

4 new i18n keys (EN).

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

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

@@ -33,6 +33,12 @@ function adminLoyaltyMerchantDetail() {
         settings: null,
         locations: [],
 
+        // Transaction categories
+        selectedCategoryStoreId: '',
+        storeCategories: [],
+        showAddCategory: false,
+        newCategoryName: '',
+
         // State
         loading: false,
         error: null,
@@ -258,6 +264,59 @@ function adminLoyaltyMerchantDetail() {
         formatNumber(num) {
             if (num === null || num === undefined) return '0';
             return new Intl.NumberFormat('en-US').format(num);
+        },
+
+        // Transaction categories
+        async loadCategoriesForStore() {
+            if (!this.selectedCategoryStoreId) {
+                this.storeCategories = [];
+                return;
+            }
+            try {
+                const response = await apiClient.get(`/admin/loyalty/stores/${this.selectedCategoryStoreId}/categories`);
+                this.storeCategories = response?.categories || [];
+            } catch (error) {
+                loyaltyMerchantDetailLog.warn('Failed to load categories:', error.message);
+                this.storeCategories = [];
+            }
+        },
+
+        async createCategory() {
+            if (!this.newCategoryName || !this.selectedCategoryStoreId) return;
+            try {
+                await apiClient.post(`/admin/loyalty/stores/${this.selectedCategoryStoreId}/categories`, {
+                    name: this.newCategoryName,
+                    display_order: this.storeCategories.length,
+                });
+                this.newCategoryName = '';
+                this.showAddCategory = false;
+                await this.loadCategoriesForStore();
+                Utils.showToast('Category created', 'success');
+            } catch (error) {
+                Utils.showToast(error.message || 'Failed to create category', 'error');
+            }
+        },
+
+        async toggleCategoryActive(cat) {
+            try {
+                await apiClient.patch(`/admin/loyalty/stores/${this.selectedCategoryStoreId}/categories/${cat.id}`, {
+                    is_active: !cat.is_active,
+                });
+                await this.loadCategoriesForStore();
+            } catch (error) {
+                Utils.showToast(error.message || 'Failed to update category', 'error');
+            }
+        },
+
+        async deleteCategory(catId) {
+            if (!confirm('Delete this category?')) return;
+            try {
+                await apiClient.delete(`/admin/loyalty/stores/${this.selectedCategoryStoreId}/categories/${catId}`);
+                await this.loadCategoriesForStore();
+                Utils.showToast('Category deleted', 'success');
+            } catch (error) {
+                Utils.showToast(error.message || 'Failed to delete category', 'error');
+            }
         }
     };
 }

app/modules/loyalty/static/store/js/loyalty-terminal.js

@@ -31,6 +31,8 @@ function storeLoyaltyTerminal() {
         // Transaction inputs
         earnAmount: null,
         selectedReward: '',
+        selectedCategory: null,
+        categories: [],
 
         // PIN entry
         showPinEntry: false,
@@ -63,6 +65,7 @@ function storeLoyaltyTerminal() {
             }
 
             await this.loadData();
+            await this.loadCategories();
 
             loyaltyTerminalLog.info('=== LOYALTY TERMINAL INITIALIZATION COMPLETE ===');
         },
@@ -279,13 +282,25 @@ function storeLoyaltyTerminal() {
             }
         },
 
+        // Load categories for this store
+        async loadCategories() {
+            try {
+                const response = await apiClient.get('/store/loyalty/categories');
+                this.categories = (response?.categories || []).filter(c => c.is_active);
+                loyaltyTerminalLog.info(`Loaded ${this.categories.length} categories`);
+            } catch (error) {
+                loyaltyTerminalLog.warn('Failed to load categories:', error.message);
+            }
+        },
+
         // Add stamp
         async addStamp() {
             loyaltyTerminalLog.info('Adding stamp...');
 
             await apiClient.post('/store/loyalty/stamp', {
                 card_id: this.selectedCard.id,
-                staff_pin: this.pinDigits
+                staff_pin: this.pinDigits,
+                category_id: this.selectedCategory || undefined,
             });
 
             Utils.showToast(I18n.t('loyalty.store.terminal.stamp_added'), 'success');
@@ -297,7 +312,7 @@ function storeLoyaltyTerminal() {
 
             await apiClient.post('/store/loyalty/stamp/redeem', {
                 card_id: this.selectedCard.id,
-                staff_pin: this.pinDigits
+                staff_pin: this.pinDigits,
             });
 
             Utils.showToast(I18n.t('loyalty.store.terminal.stamps_redeemed'), 'success');
@@ -310,7 +325,8 @@ function storeLoyaltyTerminal() {
             const response = await apiClient.post('/store/loyalty/points/earn', {
                 card_id: this.selectedCard.id,
                 purchase_amount_cents: Math.round(this.earnAmount * 100),
-                staff_pin: this.pinDigits
+                staff_pin: this.pinDigits,
+                category_id: this.selectedCategory || undefined,
             });
 
             const pointsEarned = response.points_earned || Math.floor(this.earnAmount * (this.program?.points_per_euro || 1));
@@ -329,7 +345,7 @@ function storeLoyaltyTerminal() {
             await apiClient.post('/store/loyalty/points/redeem', {
                 card_id: this.selectedCard.id,
                 reward_id: this.selectedReward,
-                staff_pin: this.pinDigits
+                staff_pin: this.pinDigits,
             });
 
             Utils.showToast(I18n.t('loyalty.store.terminal.reward_redeemed', {name: reward.name}), 'success');