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/en.json

@@ -0,0 +1,42 @@
+{
+  "title": "Shopping Cart",
+  "description": "Shopping cart management for customers",
+  "cart": {
+    "title": "Your Cart",
+    "empty": "Your cart is empty",
+    "empty_subtitle": "Add items to start shopping",
+    "continue_shopping": "Continue Shopping",
+    "proceed_to_checkout": "Proceed to Checkout"
+  },
+  "item": {
+    "product": "Product",
+    "quantity": "Quantity",
+    "price": "Price",
+    "total": "Total",
+    "remove": "Remove",
+    "update": "Update"
+  },
+  "summary": {
+    "title": "Order Summary",
+    "subtotal": "Subtotal",
+    "shipping": "Shipping",
+    "estimated_shipping": "Calculated at checkout",
+    "tax": "Tax",
+    "total": "Total"
+  },
+  "validation": {
+    "invalid_quantity": "Invalid quantity",
+    "min_quantity": "Minimum quantity is {min}",
+    "max_quantity": "Maximum quantity is {max}",
+    "insufficient_inventory": "Only {available} available"
+  },
+  "messages": {
+    "item_added": "Item added to cart",
+    "item_updated": "Cart updated",
+    "item_removed": "Item removed from cart",
+    "cart_cleared": "Cart cleared",
+    "product_not_available": "Product not available",
+    "error_adding": "Error adding item to cart",
+    "error_updating": "Error updating cart"
+  }
+}