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/src/App.tsx

@@ -4,6 +4,7 @@ import { RouterProvider } from "@tanstack/react-router";
 import { fetchMe, type SessionUser } from "./api.js";
 import { Login } from "./Login.js";
 import { queryClient } from "./lib/query.js";
+import { setLanguage } from "./lib/i18n/index.js";
 import { router } from "./router.js";
 
 // App root: bootstraps the session (cookie-based, from /api/auth/me), then hands
@@ -22,6 +23,12 @@ export function App() {
       .finally(() => setLoading(false));
   }, []);
 
+  // Apply the signed-in user's preferred language whenever it resolves/changes
+  // (login, bootstrap, or a toggle). Albanian is the default before auth resolves.
+  useEffect(() => {
+    if (user) setLanguage(user.language);
+  }, [user]);
+
   if (loading) {
     return <div className="flex h-screen items-center justify-center text-term-muted">loading…</div>;
   }