fix(audio): restart iOS voice unit in place

crates/chanora_audio/src/engine.rs

@@ -395,6 +395,22 @@ enum IosVoiceBackend {
 
 #[cfg(any(target_os = "ios", target_os = "macos"))]
 impl IosVoiceBackend {
+    fn restart(&mut self) -> Result<(), AudioError> {
+        #[cfg(target_os = "ios")]
+        {
+            match self {
+                Self::Vpio(unit) => unit.restart(),
+                Self::Raw(unit) => unit.restart(),
+            }
+        }
+        #[cfg(target_os = "macos")]
+        {
+            match self {
+                Self::Vpio(_unit) => Ok(()),
+            }
+        }
+    }
+
     fn pause(&mut self) -> Result<(), AudioError> {
         #[cfg(target_os = "ios")]
         {
@@ -1404,21 +1420,11 @@ impl AudioEngine {
     pub fn ios_restart_voice_unit(&self) -> Result<(), AudioError> {
         #[cfg(any(target_os = "ios", target_os = "macos"))]
         {
-            let backend = open_ios_voice_backend(crate::mobile_voice_backend::VoiceAudioParams {
-                handler: self.audio_handler.clone(),
-                output_gain: self.output_gain.clone(),
-                output_muted: self.output_muted.clone(),
-                voice_out_tx: self.voice_out_tx.clone(),
-                transmit_active: self.transmit_gate.flag_arc(),
-                frames_sent: self.frames_sent.clone(),
-                mic_gain: self.mic_gain,
-                voice_activity_selector: self.voice_activity_selector.clone(),
-                audio_processing_config: self.audio_processing_config.clone(),
-                audio_processing_stats: self.audio_processing_stats.clone(),
-            })?;
             let mut guard = self._ios_voice_backend.lock().unwrap();
-            *guard = Some(backend);
-            Ok(())
+            let backend = guard
+                .as_mut()
+                .ok_or_else(|| AudioError::Backend("ios voice backend not running".to_string()))?;
+            backend.restart()
         }
         #[cfg(not(any(target_os = "ios", target_os = "macos")))]
         {