Move the server to car.k8s.stinnesbeck.com

The server's host is car.k8s.stinnesbeck.com, not car.stinnesbeck.com:
IngressRoute, PUBLIC_URL (so the pairing QR code points there), the
app's pre-filled server URL and hint, and the docs. Grafana's
placeholder host follows to car-grafana.k8s.stinnesbeck.com, so one
*.k8s.stinnesbeck.com default certificate covers both. App 2.4.1 for the
new default; the server image is unchanged (its URL comes from the
manifest).

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01QLJfZQZeAKAwSqViTmLzki

app/build.gradle

@@ -34,8 +34,8 @@ android {
         applicationId "com.stinnesbeck.nilsmg4"
         minSdk 27
         targetSdk 36
-        versionCode 58
-        versionName "2.4.0"
+        versionCode 59
+        versionName "2.4.1"
 
         // Nothing about the server ships in the APK: its URL and ingest token are entered in
         // the app's Server tab (ServerConfig), and the database is only reachable by the server.