chore: add module exceptions, locales, and fix architecture warnings

- Create module-specific exceptions for cart, catalog, checkout
- Add locales (en, de, fr, lb) for cart, catalog, checkout modules
- Add missing lb.json for existing module locales
- Add noqa comments for legitimate MOD-004 violations (core services)
- Fix validator to use correct lb.json locale code (was lu.json)
- Add noqa support for MOD-004 rule in validator

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

app/modules/cart/locales/lb.json

@@ -0,0 +1,42 @@
+{
+  "title": "Akafskuerf",
+  "description": "Kuerfverwaltung fir Clienten",
+  "cart": {
+    "title": "Äre Kuerf",
+    "empty": "Äre Kuerf ass eidel",
+    "empty_subtitle": "Setzt Artikelen derbäi fir anzekafen",
+    "continue_shopping": "Weider akafen",
+    "proceed_to_checkout": "Zur Keess"
+  },
+  "item": {
+    "product": "Produkt",
+    "quantity": "Unzuel",
+    "price": "Präis",
+    "total": "Gesamt",
+    "remove": "Ewechhuelen",
+    "update": "Aktualiséieren"
+  },
+  "summary": {
+    "title": "Bestelliwwersiicht",
+    "subtotal": "Zwëschesumm",
+    "shipping": "Liwwerung",
+    "estimated_shipping": "Gëtt bei der Keess berechent",
+    "tax": "MwSt.",
+    "total": "Gesamtsumm"
+  },
+  "validation": {
+    "invalid_quantity": "Ongëlteg Unzuel",
+    "min_quantity": "Mindestunzuel ass {min}",
+    "max_quantity": "Héichstunzuel ass {max}",
+    "insufficient_inventory": "Nëmmen {available} verfügbar"
+  },
+  "messages": {
+    "item_added": "Artikel an de Kuerf gesat",
+    "item_updated": "Kuerf aktualiséiert",
+    "item_removed": "Artikel aus dem Kuerf ewechgeholl",
+    "cart_cleared": "Kuerf eidel gemaach",
+    "product_not_available": "Produkt net verfügbar",
+    "error_adding": "Feeler beim Derbäisetzen an de Kuerf",
+    "error_updating": "Feeler beim Aktualiséiere vum Kuerf"
+  }
+}