feat(web): i18n with react-i18next — Albanian default, English second

Add react-i18next with two key-parity-checked catalogs (sq default/fallback, en).
Active language driven by the logged-in user's stored preference (applied after
/me resolves); SQ/EN toggle in the header persists via PUT /api/auth/language.
Translate the booth (screen, pay/exit modal, active sessions, snapshots, status),
Login, ShiftControl, SiteSettings, PermitManager, TariffComposer.

SetupWizard deferred (its content is server-provided; needs backend catalog i18n).

apps/web/package.json

@@ -17,8 +17,10 @@
     "@radix-ui/react-tabs": "^1.1.15",
     "@tanstack/react-query": "^5.101.0",
     "@tanstack/react-router": "^1.170.16",
+    "i18next": "^26.3.1",
     "react": "19.2.7",
     "react-dom": "19.2.7",
+    "react-i18next": "^17.0.8",
     "zustand": "^5.0.14"
   },
   "devDependencies": {