fix(eq): stop the phone's FM sink from posing as the active output

Regression from the previous commit. Ranking every AudioDeviceInfo type this
build does not name individually ABOVE the built-in speaker was meant to let
a car stereo on LE Audio or an automotive bus win. It also promoted the
internal sinks a phone exposes permanently: on the Xiaomi test device
AudioManager reports TYPE_FM (14) as an output, so getActiveAudioDevice
picked it over the real speaker with nothing connected at all. Confirmed on
device:

  audio_devices.onListen -> {id=other:14:4, type=14, name=2412DPC0AG}

It then reached Dart under an `other:14:4` id whose type is neither the base
speaker nor a known one, slipped past the collision guard and had a preset
row persisted for it -- reinstating the exact symptom this series set out to
kill: a permanent green active-output dot on a device that was not connected.

Replace the deny-by-omission ranking with an explicit allow list of outputs a
user actually connects. The built-in speaker sits below all of them and above
everything else, so any sink that physically exists but is never where media
plays (TYPE_FM, TYPE_BUILTIN_SPEAKER_SAFE, telephony, remote submix) can no
longer be selected. A one-time purge clears the `other:` rows the bad build
persisted; genuine ones re-register on their next connection.

Fix the USB type constant while here: TYPE_USB_HEADSET is 22, not 14, and 14
is TYPE_FM. The Kotlin USB branch hardcoded 14 and the Dart type table
mirrored the same mistake, so the two cancelled out for real USB headsets
while making a phone's own FM sink decode as USB audio. Both now use 22.

Verified with javap against android.jar (android-36) rather than trusting the
comment that introduced the error.

lib/servicios/servicio_dispositivo_audio.dart

@@ -22,6 +22,13 @@ const prefijoPlaceholderBtName = 'bt_a2dp:name:';
 /// entry that then marked the wrong device as active forever.
 const idAltavozInterno = 'builtin_speaker';
 
+/// Id prefix for outputs the native layer does not name individually
+/// (`other:<AudioDeviceInfo type>:<address>`): LE Audio stereos, car buses,
+/// hearing aids, docks. Kept distinct from every other id namespace so such a
+/// device can never collide with [idAltavozInterno], and so a bad batch of them
+/// can be purged wholesale.
+const prefijoDispositivoOtro = 'other:';
+
 /// Abstract service for audio device detection.
 ///
 /// Implementations:
@@ -79,7 +86,11 @@ abstract class ServicioDispositivoAudio {
 ///   2  → altavozInterno (builtin_speaker)
 ///   3  → auricularesCable (wired_headset)
 ///   8  → bluetoothA2dp (`bt_a2dp:<MAC>`)
-///   14 → usbAudio (`usb_headset:<address>`)
+///   22 → usbAudio (`usb_headset:<address>`)
+///
+/// Values match `AudioDeviceInfo.TYPE_*`. Note 22, NOT 14: type 14 is
+/// `TYPE_FM`, an output plenty of phones expose permanently, and mapping it to
+/// USB audio made a phone's own FM sink look like a connected headset.
 class ServicioDispositivoAudioReal extends ServicioDispositivoAudio {
   static const _channelName = 'pluriwave/audio_devices';
 
@@ -189,7 +200,7 @@ class ServicioDispositivoAudioReal extends ServicioDispositivoAudio {
         return TipoDispositivo.auricularesCable;
       case 8:
         return TipoDispositivo.bluetoothA2dp;
-      case 14:
+      case 22:
         return TipoDispositivo.usbAudio;
       default:
         return TipoDispositivo.desconocido;

lib/servicios/servicio_ecualizador.dart

@@ -4,7 +4,8 @@ import 'package:shared_preferences/shared_preferences.dart';
 
 import '../modelos/preset_ecualizador.dart';
 import 'persistencia_tolerante.dart';
-import 'servicio_dispositivo_audio.dart' show idAltavozInterno;
+import 'servicio_dispositivo_audio.dart'
+    show idAltavozInterno, prefijoDispositivoOtro;
 
 class ConfiguracionEcualizador {
   const ConfiguracionEcualizador({
@@ -106,9 +107,64 @@ class ServicioEcualizador {
     final prefs = await _resolverPrefs();
     if (prefs.getBool(_keyColisionBasePurgaHecha) ?? false) return;
     await _purgarDeviceId(prefs, idAltavozInterno);
+    await _purgarPrefijoDispositivo(prefs, prefijoDispositivoOtro);
     await prefs.setBool(_keyColisionBasePurgaHecha, true);
   }
 
+  /// Removes every device-keyed entry whose id starts with [prefijo].
+  ///
+  /// Used for the `other:` namespace: a build that ranked every unlisted
+  /// `AudioDeviceInfo` type above the phone speaker selected permanent internal
+  /// sinks (TYPE_FM on Xiaomi, TYPE_BUILTIN_SPEAKER_SAFE elsewhere) as the
+  /// active output and persisted rows for them. Genuine external outputs in
+  /// this namespace are re-registered on their next connection, so clearing the
+  /// whole prefix costs nothing and needs no per-type knowledge here.
+  Future<void> _purgarPrefijoDispositivo(
+    SharedPreferences prefs,
+    String prefijo,
+  ) async {
+    final presetsPorDispositivo = _leerMapa(prefs, _keyPresetsPorDispositivo);
+    final dispositivos = presetsPorDispositivo.keys
+        .where((clave) => clave.startsWith(prefijo))
+        .toList();
+
+    final nombres = _leerMapaStrings(prefs, _keyNombresDispositivos);
+    final nombresAPurgar = nombres.keys
+        .where((clave) => clave.startsWith(prefijo))
+        .toList();
+
+    final matriz = _leerMapa(prefs, _keyPresetsMatriz);
+    final matrizAPurgar = matriz.keys.where((clave) {
+      final separador = clave.indexOf(':');
+      if (separador == -1) return false;
+      return clave.substring(separador + 1).startsWith(prefijo);
+    }).toList();
+
+    for (final clave in dispositivos) {
+      presetsPorDispositivo.remove(clave);
+    }
+    for (final clave in nombresAPurgar) {
+      nombres.remove(clave);
+    }
+    for (final clave in matrizAPurgar) {
+      matriz.remove(clave);
+    }
+
+    if (dispositivos.isNotEmpty) {
+      await _guardarMapa(
+        prefs,
+        _keyPresetsPorDispositivo,
+        presetsPorDispositivo,
+      );
+    }
+    if (nombresAPurgar.isNotEmpty) {
+      await _guardarMapaStrings(prefs, _keyNombresDispositivos, nombres);
+    }
+    if (matrizAPurgar.isNotEmpty) {
+      await _guardarMapa(prefs, _keyPresetsMatriz, matriz);
+    }
+  }
+
   /// Removes every trace of [deviceId] from the three device-keyed SP maps.
   ///
   /// Shared by the guarded migrations and by [eliminarDispositivo]; each map is