Set audioSession.type to playback in sheet music app (#489)

Use the Audio Session API to declare audio as media playback so the
platform handles it correctly: background audio, lock screen controls,
Dynamic Island integration, and bypassing the iOS silent switch.

Author: mel-anthropic

examples/sheet-music-server/src/mcp-app.ts

@@ -30,6 +30,17 @@ const statusEl = document.getElementById("status")!;
 const sheetMusicEl = document.getElementById("sheet-music")!;
 const audioControlsEl = document.getElementById("audio-controls")!;
 
+// =============================================================================
+// Audio Session
+// =============================================================================
+
+// Declare this app's audio as media playback so the platform can handle it
+// correctly: background audio, lock screen controls, Dynamic Island, and
+// bypassing the iOS silent switch. See https://w3c.github.io/audio-session/
+if ("audioSession" in navigator) {
+  (navigator.audioSession as { type: string }).type = "playback";
+}
+
 // =============================================================================
 // ABC Rendering
 // =============================================================================