feat(android): rename display name to "Punktfunk" + drop the Settings "Done" button

- Display name capitalized: app_name (launcher label + permission dialogs) and the connect-screen
  header are now "Punktfunk". Package/applicationId/service names stay lowercase.
- Settings: removed the redundant "Done" button (the bottom tab bar is the navigation; system Back
  still returns to Connect). Dropped the now-unused imports.

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

clients/android/app/src/main/res/values/strings.xml

@@ -1,4 +1,4 @@
 <?xml version="1.0" encoding="utf-8"?>
 <resources>
-    <string name="app_name">punktfunk</string>
+    <string name="app_name">Punktfunk</string>
 </resources>