feat(updater): disable the in-app updater in containerized installs

The Docker image already injects CONTAINERIZED=true; consume it via config('invoiceshelf.containerized'), expose it on /app/version, block the update endpoints + console command, and show a 'docker compose pull' panel instead of the updater. Adds missing i18n keys.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

app/Http/Controllers/AppVersionController.php

@@ -27,6 +27,7 @@ class AppVersionController extends Controller
         return response()->json([
             'version' => $version,
             'channel' => $channel,
+            'containerized' => (bool) config('invoiceshelf.containerized'),
         ]);
     }
 }