Fix audio clock drift and adaptive jitter buffering

clients/windows/VoiceCat.App/Audio/WasapiAudioBackend.cs

@@ -34,7 +34,7 @@ public sealed class WasapiAudioBackend : IAudioDeviceBackend
     private sealed class Playback : IAudioPlayback
     {
         private readonly string? deviceId;
-        private readonly PcmRing pcm = new(32768);
+        private readonly AdaptivePcmBuffer pcm = new(2);
         private readonly ManualResetEventSlim initialized = new(false);
         private readonly Thread thread;
         private volatile bool running = true;
@@ -47,6 +47,7 @@ public sealed class WasapiAudioBackend : IAudioDeviceBackend
             thread.Start();
             if (!initialized.Wait(5000) || !ready) { Dispose(); throw new InvalidOperationException("WASAPI playback could not start."); }
         }
+        public int BufferMilliseconds { get => pcm.BufferMilliseconds; set => pcm.BufferMilliseconds = value; }
         public void Write(ReadOnlySpan<short> stereoPcm) => pcm.TryWrite(stereoPcm);
         private unsafe void Work()
         {
@@ -68,7 +69,6 @@ public sealed class WasapiAudioBackend : IAudioDeviceBackend
                 render = (IAudioRenderClient)output;
                 if (client.Start() < 0) return;
                 ready = true; initialized.Set();
-                Span<short> discard = stackalloc short[1920];
                 while (running)
                 {
                     bufferReady.WaitOne(20); // Scheduling wait is outside the buffer-fill cycle.
@@ -77,8 +77,6 @@ public sealed class WasapiAudioBackend : IAudioDeviceBackend
                     if (frames == 0) continue;
                     if (render.GetBuffer(frames, out nint buffer) < 0) break;
                     var destination = new Span<short>((void*)buffer, checked((int)frames * 2));
-                    // Keep queued playback bounded to ~120 ms, then fill underflow with silence.
-                    while (pcm.Count > 11520) pcm.Read(discard);
                     int count = pcm.Read(destination); destination[count..].Clear();
                     if (render.ReleaseBuffer(frames, 0) < 0) break;
                 }