App 2.27.1: accent colour only for styles drawn in it

Settings → Display now has the Overview style first with the accent
colour beside it; for styles with their own palette the accent field is
greyed out with a note. Styles are an enum, OverviewStyle, with
usesAccent (unit-tested). Emulator only.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01LhzAVaUyqcw5PkGjz4mWW6

app/build.gradle

@@ -34,8 +34,8 @@ android {
         applicationId "com.stinnesbeck.nilsmg4"
         minSdk 27
         targetSdk 36
-        versionCode 121
-        versionName "2.27.0"
+        versionCode 122
+        versionName "2.27.1"
 
         // 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.