feat(roles): add admin store roles page, permission i18n, and menu integration

- Add admin store roles page with merchant→store cascading for superadmin
  and store-only selection for platform admin
- Add permission catalog API with translated labels/descriptions (en/fr/de/lb)
- Add permission translations to all 15 module locale files (60 files total)
- Add info icon tooltips for permission descriptions in role editor
- Add store roles menu item and admin menu item in module definition
- Fix store-selector.js URL construction bug when apiEndpoint has query params
- Add admin store roles API (CRUD + platform scoping)
- Add integration tests for admin store roles and permission catalog

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

app/modules/billing/locales/lb.json

@@ -134,5 +134,17 @@
         "invoices": "Rechnungen",
         "account_settings": "Kont-Astellungen",
         "billing": "Ofrechnung"
+    },
+    "permissions": {
+        "view_tiers": "Tariffer kucken",
+        "view_tiers_desc": "Detailer vun den Abonnement-Tariffer kucken",
+        "manage_tiers": "Tariffer verwalten",
+        "manage_tiers_desc": "Abonnement-Tariffer erstellen a konfiguréieren",
+        "view_subscriptions": "Abonnementer kucken",
+        "view_subscriptions_desc": "Abonnementdetailer kucken",
+        "manage_subscriptions": "Abonnementer verwalten",
+        "manage_subscriptions_desc": "Abonnementer an Ofrechnung verwalten",
+        "view_invoices": "Rechnunge kucken",
+        "view_invoices_desc": "Rechnungen an Ofrechnungsverlaf kucken"
     }
 }