App 2.16.3: full screen stays with drop-downs and dialogs

Opening a drop-down or a dialog brought the car's bars back until it
closed: each is a window of its own, and the system shows the bars when
a window without the full-screen flags takes focus.

- The drop-downs (upload frequency, tyre pressure unit, accent colour)
  are now single-choice buttons on the page: no extra window, one tap
  instead of two, full touch targets, the choice in the accent colour.
- Dialogs (About, update, pairing, phone settings, trip reset, date
  picker) are shown unfocusable, given the activity's full-screen
  flags, and only then allowed focus. None of them takes typing, which
  an unfocusable window would block.

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 86
-        versionName "2.16.2"
+        versionCode 87
+        versionName "2.16.3"
 
         // 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.