feat(proxy-engine): add live TTS streaming interactions and incoming number range support

rust/crates/proxy-engine/src/audio_player.rs

@@ -208,14 +208,23 @@ pub fn load_prompt_pcm_frames(wav_path: &str) -> Result<Vec<Vec<f32>>, String> {
         return Ok(vec![]);
     }
 
+    pcm_to_mix_frames(&samples, wav_rate)
+}
+
+/// Convert PCM samples at an arbitrary rate into 48kHz 20ms mixer frames.
+pub fn pcm_to_mix_frames(samples: &[f32], sample_rate: u32) -> Result<Vec<Vec<f32>>, String> {
+    if samples.is_empty() {
+        return Ok(vec![]);
+    }
+
     // Resample to MIX_RATE (48kHz) if needed.
-    let resampled = if wav_rate != MIX_RATE {
+    let resampled = if sample_rate != MIX_RATE {
         let mut transcoder = TranscodeState::new().map_err(|e| format!("codec init: {e}"))?;
         transcoder
-            .resample_f32(&samples, wav_rate, MIX_RATE)
+            .resample_f32(samples, sample_rate, MIX_RATE)
             .map_err(|e| format!("resample: {e}"))?
     } else {
-        samples
+        samples.to_vec()
     };
 
     // Split into MIX_FRAME_SIZE (960) sample frames.