fix(devices): use real Bluetooth MAC as device identity on Android 12+

Without BLUETOOTH_CONNECT, Android 12+ returns the fixed placeholder
02:00:00:00:00:00 for every Bluetooth device's address, so all BT
devices collapsed onto the same equalizer identity and renames
appeared to duplicate devices after re-pairing.

Declare the permission, add a requestBluetoothConnect channel method
mirroring the existing notification-permission flow, guard the
placeholder in deviceToMap() with a colon-sanitized name-based
fallback id (replacing the dead 00:00:00:00:00:00 branch), and
re-emit the active device after the grant so already-connected
devices pick up their real MAC without a reconnect.

Work unit 1/2 of bt-device-identity (Kotlin plumbing).

android/app/src/main/AndroidManifest.xml

@@ -14,6 +14,7 @@
     <uses-permission android:name="android.permission.REQUEST_IGNORE_BATTERY_OPTIMIZATIONS"/>
     <uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION"/>
     <uses-permission android:name="android.permission.ACCESS_FINE_LOCATION"/>
+    <uses-permission android:name="android.permission.BLUETOOTH_CONNECT"/>
 
     <application
         android:label="PluriWave"

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

@@ -37,6 +37,8 @@ class MainActivity : AudioServiceActivity() {
     private val audioDevicesChannel = "pluriwave/audio_devices"
     private val visualizerPermissionRequestCode = 4821
     private val notificationPermissionRequestCode = 4822
+    private val bluetoothConnectPermissionRequestCode = 4823
+    private val bluetoothMacPlaceholder = "02:00:00:00:00:00"
     private var visualizer: Visualizer? = null
     private var pendingSink: EventChannel.EventSink? = null
     private var pendingArgs: Map<*, *>? = null
@@ -614,6 +616,14 @@ class MainActivity : AudioServiceActivity() {
     ) {
         super.onRequestPermissionsResult(requestCode, permissions, grantResults)
         if (requestCode == notificationPermissionRequestCode) return
+        if (requestCode == bluetoothConnectPermissionRequestCode) {
+            if (grantResults.firstOrNull() == PackageManager.PERMISSION_GRANTED) {
+                val device = getActiveAudioDevice()
+                Log.d(tag, "audio_devices.requestBluetoothConnect granted -> $device")
+                audioDevicesSink?.success(device)
+            }
+            return
+        }
         if (requestCode != visualizerPermissionRequestCode) return
 
         if (grantResults.firstOrNull() == PackageManager.PERMISSION_GRANTED) {
@@ -641,6 +651,10 @@ class MainActivity : AudioServiceActivity() {
                     Log.d(tag, "audio_devices.getActiveDevice -> $device")
                     result.success(device)
                 }
+                "requestBluetoothConnect" -> {
+                    Log.d(tag, "audio_devices.requestBluetoothConnect")
+                    result.success(requestBluetoothConnect())
+                }
                 else -> result.notImplemented()
             }
         }
@@ -660,6 +674,20 @@ class MainActivity : AudioServiceActivity() {
         )
     }
 
+    private fun requestBluetoothConnect(): Boolean {
+        if (Build.VERSION.SDK_INT < Build.VERSION_CODES.S) return true
+        if (checkSelfPermission(Manifest.permission.BLUETOOTH_CONNECT) ==
+            PackageManager.PERMISSION_GRANTED
+        ) {
+            return true
+        }
+        requestPermissions(
+            arrayOf(Manifest.permission.BLUETOOTH_CONNECT),
+            bluetoothConnectPermissionRequestCode
+        )
+        return true
+    }
+
     private fun registerAudioDeviceCallback() {
         if (Build.VERSION.SDK_INT < Build.VERSION_CODES.M) return
         val audioManager = getSystemService(Context.AUDIO_SERVICE) as AudioManager
@@ -693,11 +721,15 @@ class MainActivity : AudioServiceActivity() {
      * Returns a map describing the current active audio output device.
      *
      * Device ID format (matches spec):
-     *   - "builtin_speaker"           — TYPE_BUILTIN_SPEAKER (2)
+     *   - "builtin_speaker"              — TYPE_BUILTIN_SPEAKER (2)
-     *   - "wired_headset"             — TYPE_WIRED_HEADSET (3) or TYPE_WIRED_HEADPHONES (4)
+     *   - "wired_headset"                — TYPE_WIRED_HEADSET (3) or TYPE_WIRED_HEADPHONES (4)
-     *   - "bt_a2dp:<MAC>"             — TYPE_BLUETOOTH_A2DP (8); MAC from AudioDeviceInfo.address
+     *   - "bt_a2dp:<MAC>"                — TYPE_BLUETOOTH_A2DP (8); MAC from AudioDeviceInfo.address
-     *   - "usb_headset:<address>"     — TYPE_USB_HEADSET (14)
+     *   - "bt_a2dp:name:<productName>"   — TYPE_BLUETOOTH_A2DP (8) fallback when the MAC is absent
-     *   - "builtin_speaker"           — fallback when API < 23
+     *                                       or still the OS placeholder ("02:00:00:00:00:00", seen
+     *                                       without BLUETOOTH_CONNECT); productName colons are
+     *                                       sanitized to '-' to preserve the matrix-key delimiter
+     *   - "usb_headset:<address>"        — TYPE_USB_HEADSET (14)
+     *   - "builtin_speaker"              — fallback when API < 23
      *
      * Type int values sent to Dart match the AudioDeviceInfo.TYPE_* constants.
      */
@@ -739,9 +771,19 @@ class MainActivity : AudioServiceActivity() {
             AudioDeviceInfo.TYPE_WIRED_HEADPHONES ->
                 mapOf("id" to "wired_headset", "type" to 3, "name" to (device.productName?.toString() ?: "Wired Headphones"))
             AudioDeviceInfo.TYPE_BLUETOOTH_A2DP -> {
-                val mac = device.address?.takeIf { it.isNotBlank() } ?: "00:00:00:00:00:00"
+                // The OS reports a placeholder MAC ("02:00:00:00:00:00") when
+                // BLUETOOTH_CONNECT has not been granted; treat that (and any
+                // null/blank address) as absent instead of using it as an id.
+                val mac = device.address?.takeIf { it.isNotBlank() && it != bluetoothMacPlaceholder }
+                val id = if (mac != null) {
+                    "bt_a2dp:$mac"
+                } else {
+                    val safeProductName = (device.productName?.toString()?.takeIf { it.isNotBlank() } ?: "unknown")
+                        .replace(":", "-")
+                    "bt_a2dp:name:$safeProductName"
+                }
                 mapOf(
-                    "id" to "bt_a2dp:$mac",
+                    "id" to id,
                     "type" to 8,
                     "name" to (device.productName?.toString() ?: "Bluetooth"),
                 )