feat(aap): Also update system Bluetooth alias when renaming

After the AAP rename succeeds, try to update Android's per-device bond alias via the hidden BluetoothDevice.setAlias(String) method, so the new name also shows up in the system Bluetooth settings on this phone.

Known failure mode on Android 12+: setAlias is gated behind a Companion Device Manager (CDM) association at the service layer, and raises 'does not have a CDM association with the Bluetooth Device' for third-party apps that don't hold one. In that case, a dedicated snackbar explains that the system rename didn't go through and suggests renaming manually in system settings or re-pairing.

The AAP-level rename is always attempted first and is the load-bearing part; the system alias is a best-effort extra.

app/src/main/java/eu/darken/capod/common/bluetooth/BluetoothManager2.kt

@@ -307,6 +307,37 @@ class BluetoothManager2 @Inject constructor(
     private var _isNudgeAvailable: Boolean = true
     val isNudgeAvailable: Boolean get() = _isNudgeAvailable
 
+    /**
+     * Set the Android-local alias for a bonded [device]. Updates what Android's system Bluetooth
+     * settings display without touching the AirPods firmware itself. Uses reflection on the hidden
+     * `setAlias(String)` method because the public API 30+ variant requires `BLUETOOTH_PRIVILEGED`,
+     * which third-party apps cannot hold.
+     *
+     * Returns `true` on success, `false` if the call threw, was rejected, or returned `false`.
+     *
+     * Known failure mode on Android 12+: `SecurityException: does not have a CDM association with
+     * the Bluetooth Device`. The hidden method was moved behind a Companion Device Manager (CDM)
+     * permission check at the service layer — only apps that have explicitly requested and been
+     * granted a CDM association for this specific device can rename it. CAPod does not currently
+     * pursue a CDM association (that's a user-visible pairing flow), so setAlias is effectively
+     * unavailable on modern Android and callers should be prepared to surface a user-facing
+     * fallback when it returns false. See DeviceSettingsViewModel.setDeviceName.
+     */
+    @android.annotation.SuppressLint("MissingPermission")
+    fun setDeviceAlias(device: BluetoothDevice2, alias: String): Boolean {
+        return try {
+            val method = BluetoothDevice::class.java.getDeclaredMethod("setAlias", String::class.java)
+                .apply { isAccessible = true }
+            val result = method.invoke(device.internal, alias) as? Boolean ?: false
+            log(TAG) { "setDeviceAlias(${device.address}, $alias) -> $result" }
+            result
+        } catch (e: Exception) {
+            val cause = (e as? java.lang.reflect.InvocationTargetException)?.cause ?: e
+            log(TAG, WARN) { "setDeviceAlias(${device.address}, $alias) failed: $cause" }
+            false
+        }
+    }
+
     suspend fun nudgeConnection(device: BluetoothDevice2): Boolean = getBluetoothProfile().map { bluetoothProfile ->
         try {
             log(TAG) { "Nudging Android connection to $device" }

app/src/main/java/eu/darken/capod/main/ui/devicesettings/DeviceSettingsScreen.kt

@@ -109,6 +109,12 @@ fun DeviceSettingsScreenHost(
                         context.getString(R.string.device_settings_send_failed, event.message ?: ""),
                     )
                 }
+                DeviceSettingsViewModel.Event.SystemRenameUnavailable -> {
+                    snackbarHostState.showSnackbar(
+                        context.getString(R.string.device_settings_rename_system_unavailable),
+                        duration = androidx.compose.material3.SnackbarDuration.Long,
+                    )
+                }
             }
         }
     }

app/src/main/java/eu/darken/capod/main/ui/devicesettings/DeviceSettingsViewModel.kt

@@ -58,6 +58,7 @@ class DeviceSettingsViewModel @Inject constructor(
     sealed interface Event {
         data object OpenBluetoothSettings : Event
         data class SendFailed(val command: AapCommand, val message: String?) : Event
+        data object SystemRenameUnavailable : Event
     }
 
     val events = SingleEventFlow<Event>()
@@ -191,7 +192,25 @@ class DeviceSettingsViewModel @Inject constructor(
 
     fun setSleepDetection(enabled: Boolean) = sendProGated(AapCommand.SetSleepDetection(enabled))
 
-    fun setDeviceName(name: String) = send(AapCommand.SetDeviceName(name))
+    fun setDeviceName(name: String) = launch {
+        val address = targetAddress.value ?: return@launch
+        sendInternal(AapCommand.SetDeviceName(name))
+
+        // Also try to update the Android-local bond alias so the new name shows in Android's
+        // Bluetooth settings too. The AAP rename only changes what the AirPods themselves report;
+        // Android's system display reads from the bond database and needs a separate update.
+        val bonded = try {
+            bluetoothManager.bondedDevices().first().firstOrNull { it.address == address }
+        } catch (e: Exception) {
+            log(TAG, WARN) { "bondedDevices() failed while renaming: ${e.message}" }
+            null
+        }
+        val aliasOk = bonded?.let { bluetoothManager.setDeviceAlias(it, name) } ?: false
+        if (!aliasOk) {
+            log(TAG, WARN) { "System bond alias rename failed for $address — user must rename in system settings or re-pair" }
+            events.emit(Event.SystemRenameUnavailable)
+        }
+    }
 
     fun navToStemConfig() = launch {
         if (upgradeRepo.isPro()) {

app/src/main/res/values/strings.xml

@@ -496,6 +496,7 @@
     <string name="device_settings_rename_hint">Device name</string>
     <string name="device_settings_rename_confirm">Rename</string>
     <string name="device_settings_rename_invalid_ascii">Only ASCII characters are supported</string>
+    <string name="device_settings_rename_system_unavailable">Android didn\'t let us rename the device here. To update the name in Bluetooth settings, rename it there or re-pair the device.</string>
     <string name="device_settings_send_failed">Could not apply setting: %1$s</string>
     <string name="device_settings_category_connections_label">Connected Devices</string>
     <string name="device_settings_connected_devices_description">Other devices currently connected to these AirPods</string>