feat: improve user token handling and add club selection clearing button in settings

mobile-app/composeApp/src/androidMain/kotlin/de/tsschulz/tt_tagebuch/app/ui/AppRoot.kt

@@ -5804,7 +5804,21 @@ private fun SettingsScreen(
             .navigationBarsPadding()
             .padding(horizontal = ScreenHorizontalPadding, vertical = 16.dp),
     ) {
+        Button(
+            onClick = {
+                dependencies.applicationScope.launch {
+                    dependencies.clubManager.clearSelection()
+                }
+            },
+            modifier = Modifier
+                .fillMaxWidth()
+                .padding(bottom = 12.dp)
+                .heightIn(min = 56.dp),
+        ) {
+            Text(tr("club.change", "Verein wechseln"), style = MaterialTheme.typography.h6)
+        }
         Header(tr("mobile.more", "Mehr"))
+        
         DetailLine(tr("mobile.user", "Benutzer"), authState.username ?: "-")
         DetailLine("Backend", dependencies.apiConfig.baseUrl)
         DetailLine("Club", clubState.clubs.firstOrNull { it.id == clubState.currentClubId }?.name ?: "-")