fix(loyalty): resolve critical production readiness issues

- Add pessimistic locking (SELECT FOR UPDATE) on card write operations
  to prevent race conditions in stamp_service and points_service
- Replace 16 console.log/error/warn calls with LogConfig.createLogger()
  in 3 storefront JS files (dashboard, history, enroll)
- Delete all stale lu.json locale files across 8 modules (lb is the
  correct ISO 639-1 code for Luxembourgish)
- Update architecture rules and docs to reference lb.json not lu.json
- Add production-readiness.md report for loyalty module

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

app/modules/loyalty/static/storefront/js/loyalty-dashboard.js

@@ -1,5 +1,6 @@
 // app/modules/loyalty/static/storefront/js/loyalty-dashboard.js
 // Customer loyalty dashboard
+const loyaltyDashboardLog = window.LogConfig.loggers.loyaltyDashboard || window.LogConfig.createLogger('loyaltyDashboard');
 
 function customerLoyaltyDashboard() {
     return {
@@ -20,7 +21,7 @@ function customerLoyaltyDashboard() {
         showBarcode: false,
 
         async init() {
-            console.log('Customer loyalty dashboard initializing...');
+            loyaltyDashboardLog.info('Customer loyalty dashboard initializing...');
             await this.loadData();
         },
 
@@ -32,7 +33,7 @@ function customerLoyaltyDashboard() {
                     this.loadTransactions()
                 ]);
             } catch (error) {
-                console.error('Failed to load loyalty data:', error);
+                loyaltyDashboardLog.error('Failed to load loyalty data:', error);
             } finally {
                 this.loading = false;
             }
@@ -47,11 +48,11 @@ function customerLoyaltyDashboard() {
                     this.rewards = response.program?.points_rewards || [];
                     this.locations = response.locations || [];
                     this.walletUrls = response.wallet_urls || { google_wallet_url: null, apple_wallet_url: null };
-                    console.log('Loyalty card loaded:', this.card?.card_number);
+                    loyaltyDashboardLog.info('Loyalty card loaded:', this.card?.card_number);
                 }
             } catch (error) {
                 if (error.status === 404) {
-                    console.log('No loyalty card found');
+                    loyaltyDashboardLog.info('No loyalty card found');
                     this.card = null;
                 } else {
                     throw error;
@@ -66,7 +67,7 @@ function customerLoyaltyDashboard() {
                     this.transactions = response.transactions;
                 }
             } catch (error) {
-                console.warn('Failed to load transactions:', error.message);
+                loyaltyDashboardLog.warn('Failed to load transactions:', error.message);
             }
         },