Fix audio: send raw PCM to LiteRT-LM instead of WAV

Content.AudioBytes expects raw PCM (16kHz mono 16-bit), not WAV with
44-byte RIFF header. The header bytes were being parsed as audio samples
causing "Failed to read pcm frames, error code: -2".

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: vNeeL-code

app/src/main/kotlin/com/gemma/api/mcp/MCPServer.kt

@@ -355,7 +355,7 @@ class MCPServer(
             return ToolResult(false, "", "No microphone permission")
         }
 
-        val audioData = audioRecorder.record(duration, rawPcm = false)
+        val audioData = audioRecorder.record(duration, rawPcm = true)  // Raw PCM for LiteRT-LM
             ?: return ToolResult(false, "", "Audio recording failed")
 
         // Deliver audio bytes via callback so GemmaService can queue them for next inference

app/src/main/kotlin/com/gemma/api/ui/InputOverlay.kt

@@ -163,7 +163,7 @@ class InputOverlay(
         recordingJob = CoroutineScope(Dispatchers.Main).launch {
             Timber.i("InputOverlay: Recording up to 30s audio...")
             val audio: ByteArray? = withContext(Dispatchers.IO) {
-                audioRecorder.record(30, false)
+                audioRecorder.record(30, true)  // Raw PCM for LiteRT-LM (no WAV header)
             }
 
             // Recording finished (either released or hit 30s cap)