feat(audio): prefer native voice backends

crates/chanora_audio/src/android_voice_unit.rs

@@ -42,10 +42,7 @@ use std::sync::atomic::{AtomicBool, AtomicU32, Ordering};
 use std::sync::{Arc, Mutex};
 
 use audiopus::coder::Encoder as OpusEncoder;
-use audiopus::{
-    Application as OpusApp, Bitrate as OpusBitrate, Channels as OpusChannels,
-    SampleRate as OpusSampleRate,
-};
+use audiopus::{Application as OpusApp, Channels as OpusChannels, SampleRate as OpusSampleRate};
 use tracing::{debug, info, warn};
 
 use crate::mobile_voice_backend::{
@@ -340,9 +337,7 @@ pub struct AndroidVoiceUnit {
     output_perf: AchievedPerformanceMode,
     output_share: AchievedSharingMode,
     input_sample_rate: i32,
-    output_sample_rate: i32,
     input_frames_per_burst: i32,
-    output_frames_per_burst: i32,
 
     session_id: Option<AudioSessionId>,
 
@@ -397,7 +392,7 @@ impl AndroidVoiceUnit {
         let scratch = Arc::new(Mutex::new(Vec::with_capacity(8192)));
 
         // --- Open input stream (SDD-112) ---------------------------
-        let mut input_builder = AudioStreamBuilder::default()
+        let input_builder = AudioStreamBuilder::default()
             .set_direction::<OboeInput>()
             .set_sample_rate(cfg.sample_rate as i32)
             .set_channel_count::<Mono>()
@@ -583,9 +578,7 @@ impl AndroidVoiceUnit {
             output_perf,
             output_share,
             input_sample_rate,
-            output_sample_rate,
             input_frames_per_burst,
-            output_frames_per_burst,
             session_id,
             hw_effects,
             event_tx,