fix(auto): clear stuck bluetooth EQ selection on device disconnect

The advanced EQ device list kept the green-dot selection on the last
connected Bluetooth device after it disconnected, instead of falling
back to the default preset.

- MainActivity.kt: onAudioDevicesRemoved recomputed the active output
  device via AudioManager.getDevices(), which can still momentarily
  report the just-removed sink (observed on Bluetooth A2DP). Removed
  device ids are now excluded explicitly instead of trusting
  getDevices() to already be current.
- estado_ecualizador.dart: cambiarMultiDeviceEnabled() re-seeds
  dispositivoActualId from a fresh query when the toggle turns back
  on, matching cargarPersistido(), so a stale id from before the
  toggle flip can't leave the dot pinned to a disconnected device.

android/app/src/main/kotlin/es/freetimelab/pluriwave/MainActivity.kt

@@ -1051,7 +1051,12 @@ class MainActivity : AudioServiceActivity() {
 
             override fun onAudioDevicesRemoved(removedDevices: Array<out AudioDeviceInfo>) {
                 // Emit the new active device after something disconnects.
-                val device = getActiveAudioDevice()
+                // AudioManager.getDevices() can still momentarily report a
+                // just-removed sink (observed on Bluetooth A2DP), so the
+                // removed ids are excluded explicitly instead of trusting
+                // getDevices() to already be up to date.
+                val excludedIds = removedDevices.map { it.id }.toSet()
+                val device = getActiveAudioDevice(excludeIds = excludedIds)
                 Log.d(tag, "audio_devices.onDevicesRemoved active=$device")
                 mainHandler.post { audioDevicesSink?.success(device) }
             }
@@ -1083,7 +1088,7 @@ class MainActivity : AudioServiceActivity() {
      *
      * Type int values sent to Dart match the AudioDeviceInfo.TYPE_* constants.
      */
-    private fun getActiveAudioDevice(): Map<String, Any> {
+    private fun getActiveAudioDevice(excludeIds: Set<Int> = emptySet()): Map<String, Any> {
         if (Build.VERSION.SDK_INT < Build.VERSION_CODES.M) {
             return mapOf("id" to "builtin_speaker", "type" to 2, "name" to "Speaker")
         }
@@ -1099,7 +1104,7 @@ class MainActivity : AudioServiceActivity() {
             AudioDeviceInfo.TYPE_BUILTIN_SPEAKER,
         )
         val best = outputs
-            .filter { it.isSink }
+            .filter { it.isSink && it.id !in excludeIds }
             .sortedBy { device ->
                 val idx = priorityOrder.indexOf(device.type)
                 if (idx == -1) Int.MAX_VALUE else idx