feat: full WSL2 audio support and Windows audio stability fix

pkg/audio/common.go

@@ -0,0 +1,13 @@
+package audio
+
+// Shared constants
+const (
+	frameSamples        = 960 // 20ms at 48kHz
+	captureFrameSamples = 960 // 20ms at 48kHz
+)
+
+// UserSettings represents per-user audio configuration
+type UserSettings struct {
+	Volume float32 // 0.0 - 1.0 (or higher for boost)
+	Muted  bool
+}