docs: clarify run-as requires debug build for MAC injection

Address PR review comment: run-as only works on debuggable builds.
Add prerequisite note directing users to install the debug/nightly APK.
Remove the alternative adb settings method which also requires
elevated privileges.

Author: teng-lin

README.md

@@ -75,11 +75,13 @@ Until then, you must xposed. I used to provide a non-xposed method too, where th
 
 #### Setup for OxygenOS/ColorOS 16 (Non-rooted)
 
-For multi-device audio switching to work properly on non-rooted OxygenOS 16, you need to inject your phone's Bluetooth MAC address into the app's settings. This is a one-time setup:
+For multi-device audio switching to work properly on non-rooted OxygenOS 16, you need to inject your phone's Bluetooth MAC address into the app's settings. This is a one-time setup.
+
+> [!IMPORTANT]
+> The `run-as` command only works with **debug builds** (e.g., the nightly APK from CI). If you installed a release build, reinstall with the debug APK first.
 
 1. **Get your phone's Bluetooth MAC address:**
    - Go to Settings → About → Device Details → Bluetooth Address
-   - Or use: `adb shell settings get secure bluetooth_address` (requires running once with a recently-root device or use the Settings method)
 
 2. **Inject the MAC address via adb:**
    ```bash

android/app/src/main/java/me/kavishdevar/librepods/services/AirPodsService.kt

@@ -2547,35 +2547,31 @@ class AirPodsService : Service(), SharedPreferences.OnSharedPreferenceChangeList
 
                         try {
                             while (socket.isConnected) {
-                                socket.let { it ->
-                                    val buffer = ByteArray(1024)
-                                    val bytesRead = it.inputStream.read(buffer)
-                                    var data: ByteArray
-                                    if (bytesRead > 0) {
-                                        data = buffer.copyOfRange(0, bytesRead)
-                                        sendBroadcast(Intent(AirPodsNotifications.AIRPODS_DATA).apply {
-                                            putExtra("data", buffer.copyOfRange(0, bytesRead))
-                                        })
-                                        val bytes = buffer.copyOfRange(0, bytesRead)
-                                        val formattedHex = bytes.joinToString(" ") { "%02X".format(it) }
-//                                        CrossDevice.sendReceivedPacket(bytes)
-                                        updateNotificationContent(
-                                            true,
-                                            sharedPreferences.getString("name", device.name),
-                                            batteryNotification.getBattery()
-                                        )
-
-                                        aacpManager.receivePacket(data)
+                                val buffer = ByteArray(1024)
+                                val bytesRead = socket.inputStream.read(buffer)
+                                if (bytesRead > 0) {
+                                    val data = buffer.copyOfRange(0, bytesRead)
+                                    sendBroadcast(Intent(AirPodsNotifications.AIRPODS_DATA).apply {
+                                        putExtra("data", buffer.copyOfRange(0, bytesRead))
+                                    })
+                                    val bytes = buffer.copyOfRange(0, bytesRead)
+                                    val formattedHex = bytes.joinToString(" ") { "%02X".format(it) }
+//                                    CrossDevice.sendReceivedPacket(bytes)
+                                    updateNotificationContent(
+                                        true,
+                                        sharedPreferences.getString("name", device.name),
+                                        batteryNotification.getBattery()
+                                    )
 
-                                        if (!isHeadTrackingData(data)) {
-                                            Log.d("AirPodsData", "Data received: $formattedHex")
-                                            logPacket(data, "AirPods")
-                                        }
+                                    aacpManager.receivePacket(data)
 
-                                    } else if (bytesRead == -1) {
-                                        Log.d("AirPods Service", "Socket closed (bytesRead = -1)")
-                                        break
+                                    if (!isHeadTrackingData(data)) {
+                                        Log.d("AirPodsData", "Data received: $formattedHex")
+                                        logPacket(data, "AirPods")
                                     }
+                                } else if (bytesRead == -1) {
+                                    Log.d("AirPods Service", "Socket closed (bytesRead = -1)")
+                                    break
                                 }
                             }
                             Log.d("AirPods Service", "Socket closed")