Remove TUI voice transcription feature (#16114)

Removes the partially-completed TUI composer voice transcription flow,
including its feature flag, app events, and hold-to-talk state machine.

codex-rs/tui/src/lib.rs

@@ -155,21 +155,13 @@ mod version;
 mod voice;
 #[cfg(all(not(target_os = "linux"), not(feature = "voice-input")))]
 mod voice {
-    use crate::app_event::AppEvent;
     use crate::app_event_sender::AppEventSender;
     use codex_core::config::Config;
     use codex_protocol::protocol::RealtimeAudioFrame;
     use std::sync::Arc;
-    use std::sync::Mutex;
     use std::sync::atomic::AtomicBool;
     use std::sync::atomic::AtomicU16;
 
-    pub struct RecordedAudio {
-        pub data: Vec<i16>,
-        pub sample_rate: u32,
-        pub channels: u16,
-    }
-
     pub struct VoiceCapture;
 
     pub(crate) struct RecordingMeterState;
@@ -177,34 +169,16 @@ mod voice {
     pub(crate) struct RealtimeAudioPlayer;
 
     impl VoiceCapture {
-        pub fn start() -> Result<Self, String> {
-            Err("voice input is unavailable in this build".to_string())
-        }
-
         pub fn start_realtime(_config: &Config, _tx: AppEventSender) -> Result<Self, String> {
             Err("voice input is unavailable in this build".to_string())
         }
 
-        pub fn stop(self) -> Result<RecordedAudio, String> {
-            Err("voice input is unavailable in this build".to_string())
-        }
-
-        pub fn data_arc(&self) -> Arc<Mutex<Vec<i16>>> {
-            Arc::new(Mutex::new(Vec::new()))
-        }
+        pub fn stop(self) {}
 
         pub fn stopped_flag(&self) -> Arc<AtomicBool> {
             Arc::new(AtomicBool::new(true))
         }
 
-        pub fn sample_rate(&self) -> u32 {
-            0
-        }
-
-        pub fn channels(&self) -> u16 {
-            0
-        }
-
         pub fn last_peak_arc(&self) -> Arc<AtomicU16> {
             Arc::new(AtomicU16::new(0))
         }
@@ -231,18 +205,6 @@ mod voice {
 
         pub(crate) fn clear(&self) {}
     }
-
-    pub fn transcribe_async(
-        id: String,
-        _audio: RecordedAudio,
-        _context: Option<String>,
-        tx: AppEventSender,
-    ) {
-        tx.send(AppEvent::TranscriptionFailed {
-            id,
-            error: "voice input is unavailable in this build".to_string(),
-        });
-    }
 }
 
 mod wrapping;