Native calls: route audio to the speaker by default (was earpiece)

The .voiceChat AVAudioSession mode defaults to the earpiece, so call audio came
out of the earpiece and only settled after mute/unmute toggling. Switch to
.videoChat + .defaultToSpeaker + allow Bluetooth so audio goes to the loudspeaker
by default while wired/BT headsets still win. Add preferSpeaker() (override to
speaker when on the built-in receiver) in didActivate AND after mic toggles (the
route can flip back to earpiece on unmute). Report the chosen route in telemetry.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

mobile/plugins/native-call/ios/Sources/NativeCallPlugin/NativeCallPlugin.swift

@@ -93,6 +93,16 @@ public class NativeCallPlugin: CAPPlugin, CAPBridgedPlugin, PKPushRegistryDelega
         Task { await r?.disconnect() }
     }
 
+    // Route call audio to the LOUDSPEAKER when we'd otherwise be on the quiet earpiece. Guarded so a connected
+    // wired/Bluetooth headset (any non-receiver route) still wins. Re-asserted on mute toggles because enabling
+    // the mic can flip the route back to the earpiece.
+    private func preferSpeaker() {
+        let s = AVAudioSession.sharedInstance()
+        if s.currentRoute.outputs.contains(where: { $0.portType == .builtInReceiver }) {
+            try? s.overrideOutputAudioPort(.speaker)
+        }
+    }
+
     // MARK: - JS-callable methods
 
     @objc func getToken(_ call: CAPPluginCall) { call.resolve(["token": voipToken]) }
@@ -285,7 +295,10 @@ public class NativeCallPlugin: CAPPlugin, CAPBridgedPlugin, PKPushRegistryDelega
 
     public func provider(_ provider: CXProvider, perform action: CXSetMutedCallAction) {
         let r = room
-        Task { try? await r?.localParticipant.setMicrophone(enabled: !action.isMuted) }
+        Task { [weak self] in
+            try? await r?.localParticipant.setMicrophone(enabled: !action.isMuted)
+            self?.preferSpeaker() // toggling the mic can flip the route back to the earpiece — re-assert speaker
+        }
         notifyListeners("setMuted", data: ["callUUID": action.callUUID.uuidString, "muted": action.isMuted])
         action.fulfill()
     }
@@ -295,9 +308,14 @@ public class NativeCallPlugin: CAPPlugin, CAPBridgedPlugin, PKPushRegistryDelega
     // dead mic / no-audio and late speaker routing. Don't call setActive(true): CallKit already activated it.
     public func provider(_ provider: CXProvider, didActivate audioSession: AVAudioSession) {
         do {
-            try audioSession.setCategory(.playAndRecord, mode: .voiceChat, options: [.mixWithOthers])
+            // Route to the LOUDSPEAKER by default (earpiece was the .voiceChat default). .videoChat +
+            // .defaultToSpeaker prefers the speaker while still letting wired/Bluetooth headsets win.
+            try audioSession.setCategory(.playAndRecord, mode: .videoChat,
+                                        options: [.defaultToSpeaker, .allowBluetooth, .allowBluetoothA2DP])
             try AudioManager.shared.setEngineAvailability(.default)
-            notifyListeners("audioActivated", data: ["ok": true])
+            preferSpeaker() // belt-and-braces: if we still landed on the earpiece, force the speaker
+            let route = audioSession.currentRoute.outputs.first?.portType.rawValue ?? "none"
+            notifyListeners("audioActivated", data: ["ok": true, "route": route])
         } catch {
             notifyListeners("audioActivated", data: ["ok": false, "error": String(describing: error)])
         }