fix: respect external USB-C microphone for voice message recording

overrideOutputAudioPort(.speaker) forces both output and input to
built-in devices, ignoring external USB-C microphones (e.g. wireless
mic receivers) that the user selected in iOS Settings.

After the override, check availableInputs for non-built-in, non-bluetooth,
non-headphone input devices and restore them as preferred input.

This preserves existing behavior when no external device is connected.

Fixes: voice messages ignore USB-C microphone on iOS 26+

Author: hanxiao

submodules/TelegramAudio/Sources/ManagedAudioSession.swift

@@ -1065,6 +1065,17 @@ public final class ManagedAudioSessionImpl: NSObject, ManagedAudioSession {
             switch updatedType {
                 case .record(false, _, _):
                     try AVAudioSession.sharedInstance().overrideOutputAudioPort(.speaker)
+                    // overrideOutputAudioPort(.speaker) forces both output AND input
+                    // to built-in devices. If an external input device (e.g. USB-C
+                    // microphone) is connected, restore it as the preferred input.
+                    if let routes = AVAudioSession.sharedInstance().availableInputs {
+                        for route in routes {
+                            if route.portType != .builtInMic && !bluetoothPortTypes.contains(route.portType) && route.portType != .headphones {
+                                let _ = try? AVAudioSession.sharedInstance().setPreferredInput(route)
+                                break
+                            }
+                        }
+                    }
                 case .voiceCall, .playWithPossiblePortOverride, .record(true, _, _):
                     try AVAudioSession.sharedInstance().overrideOutputAudioPort(.none)
                     if let routes = AVAudioSession.sharedInstance().availableInputs {