Leave the server when the app is swiped away

The process lived on without a screen, or was killed without a word, and
the server held our identity as a ghost until it timed out, refusing a
reconnect in the meantime as a clone.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

android/app/src/main/java/com/ts3client/android/ConnectionService.kt

@@ -12,6 +12,7 @@ import android.net.wifi.WifiManager
 import android.os.PowerManager
 import androidx.lifecycle.LifecycleService
 import androidx.lifecycle.lifecycleScope
+import kotlinx.coroutines.Dispatchers
 import kotlinx.coroutines.delay
 import kotlinx.coroutines.flow.collectLatest
 import kotlinx.coroutines.launch
@@ -66,6 +67,18 @@ class ConnectionService : LifecycleService() {
         return START_NOT_STICKY
     }
 
+    /**
+     * The user swiped the app away: they are done with it, connection included. Leaving
+     * properly spares the server a ghost that would hold our identity until it times out.
+     */
+    override fun onTaskRemoved(rootIntent: Intent?) {
+        super.onTaskRemoved(rootIntent)
+        lifecycleScope.launch(Dispatchers.IO) {
+            sessions.leave()
+            stopSelf()
+        }
+    }
+
     override fun onDestroy() {
         wifiLock.release()
         wakeLock.release()

android/app/src/main/java/com/ts3client/android/SessionController.kt

@@ -162,6 +162,12 @@ class SessionController(private val context: Context) {
         session.disconnect()
     }
 
+    /** Leaves the server before returning, for when the app goes away with the connection. */
+    fun leave() {
+        network.leaving()
+        session.shutdown()
+    }
+
     // ---- bookmarks ----
 
     fun addBookmark(label: String, address: String, nickname: String, password: String) {