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-enroll.js

@@ -1,5 +1,6 @@
 // app/modules/loyalty/static/storefront/js/loyalty-enroll.js
 // Self-service loyalty enrollment
+const loyaltyEnrollLog = window.LogConfig.loggers.loyaltyEnroll || window.LogConfig.createLogger('loyaltyEnroll');
 
 function customerLoyaltyEnroll() {
     return {
@@ -28,7 +29,7 @@ function customerLoyaltyEnroll() {
         showTerms: false,
 
         async init() {
-            console.log('Customer loyalty enroll initializing...');
+            loyaltyEnrollLog.info('Customer loyalty enroll initializing...');
             await this.loadProgram();
         },
 
@@ -38,14 +39,14 @@ function customerLoyaltyEnroll() {
                 const response = await apiClient.get('/storefront/loyalty/program');
                 if (response) {
                     this.program = response;
-                    console.log('Program loaded:', this.program.display_name);
+                    loyaltyEnrollLog.info('Program loaded:', this.program.display_name);
                 }
             } catch (error) {
                 if (error.status === 404) {
-                    console.log('No loyalty program available');
+                    loyaltyEnrollLog.info('No loyalty program available');
                     this.program = null;
                 } else {
-                    console.error('Failed to load program:', error);
+                    loyaltyEnrollLog.error('Failed to load program:', error);
                     this.error = I18n.t('loyalty.enrollment.errors.load_failed');
                 }
             } finally {
@@ -73,7 +74,7 @@ function customerLoyaltyEnroll() {
 
                 if (response) {
                     const cardNumber = response.card?.card_number || response.card_number;
-                    console.log('Enrollment successful:', cardNumber);
+                    loyaltyEnrollLog.info('Enrollment successful:', cardNumber);
 
                     // Store wallet URLs for the success page (no auth needed)
                     if (response.wallet_urls) {
@@ -87,7 +88,7 @@ function customerLoyaltyEnroll() {
                     window.location.href = successUrl;
                 }
             } catch (error) {
-                console.error('Enrollment failed:', error);
+                loyaltyEnrollLog.error('Enrollment failed:', error);
                 if (error.message?.includes('already')) {
                     this.error = I18n.t('loyalty.enrollment.errors.email_exists');
                 } else {