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/analytics/locales/lu.json

@@ -1,17 +0,0 @@
-{
-  "analytics": {
-    "page_title": "Analysen",
-    "dashboard_title": "Analyse-Dashboard",
-    "dashboard_subtitle": "Kuckt Är Buttek Leeschtungsmetriken an Abléck",
-    "period_7d": "Lescht 7 Deeg",
-    "period_30d": "Lescht 30 Deeg",
-    "period_90d": "Lescht 90 Deeg",
-    "period_1y": "Lescht Joer",
-    "imports_count": "Importer",
-    "products_added": "Produkter bäigesat",
-    "inventory_locations": "Lagerplazen",
-    "data_since": "Donnéeë vun",
-    "loading": "Analysen ginn gelueden...",
-    "error_loading": "Analysedonnéeën konnten net geluede ginn"
-  }
-}