feat(loyalty): add customer autocomplete to terminal search

Terminal search now shows live autocomplete suggestions as the user
types (debounced 300ms, min 2 chars). Dropdown shows matching customers
with avatar, name, email, card number, and points balance. Uses the
existing GET /store/loyalty/cards?search= endpoint (limit=5).

Selecting a result loads the full card details via the lookup endpoint.
Enter key still works for exact lookup. No new dependencies — uses
native Alpine.js dropdown, no Tom Select needed.

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

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

@@ -23,6 +23,9 @@ function storeLoyaltyTerminal() {
         searchQuery: '',
         lookingUp: false,
         selectedCard: null,
+        searchResults: [],
+        showSearchDropdown: false,
+        _searchTimeout: null,
 
         // Transaction inputs
         earnAmount: null,
@@ -146,6 +149,58 @@ function storeLoyaltyTerminal() {
             }
         },
 
+        // Debounced search for autocomplete suggestions
+        debouncedSearchCustomers() {
+            if (this._searchTimeout) clearTimeout(this._searchTimeout);
+            if (!this.searchQuery || this.searchQuery.length < 2) {
+                this.searchResults = [];
+                this.showSearchDropdown = false;
+                return;
+            }
+            this._searchTimeout = setTimeout(() => this.searchCustomers(), 300);
+        },
+
+        async searchCustomers() {
+            try {
+                const params = new URLSearchParams({
+                    search: this.searchQuery,
+                    limit: '5',
+                    is_active: 'true'
+                });
+                const response = await apiClient.get(`/store/loyalty/cards?${params}`);
+                if (response && response.cards) {
+                    this.searchResults = response.cards;
+                    this.showSearchDropdown = this.searchResults.length > 0;
+                }
+            } catch (error) {
+                loyaltyTerminalLog.warn('Search failed:', error.message);
+                this.searchResults = [];
+                this.showSearchDropdown = false;
+            }
+        },
+
+        // Select a customer from autocomplete dropdown
+        async selectCustomer(card) {
+            this.showSearchDropdown = false;
+            this.searchResults = [];
+            this.lookingUp = true;
+
+            try {
+                // Use the lookup endpoint to get full card details
+                const response = await apiClient.get(`/store/loyalty/cards/lookup?q=${encodeURIComponent(card.card_number)}`);
+                if (response) {
+                    this.selectedCard = response;
+                    this.searchQuery = '';
+                    loyaltyTerminalLog.info('Customer selected:', this.selectedCard.customer_name);
+                }
+            } catch (error) {
+                Utils.showToast(I18n.t('loyalty.store.terminal.error_lookup', {message: error.message}), 'error');
+                loyaltyTerminalLog.error('Lookup failed:', error);
+            } finally {
+                this.lookingUp = false;
+            }
+        },
+
         // Clear selected customer
         clearCustomer() {
             this.selectedCard = null;