Move tray state into createTray closure

Removes top-level let trayInstance, opts, currentTitle, currentArtist
and the top-level buildMenu function. All mutable state and buildMenu
now live inside the createTray closure. Public API and behaviour are
unchanged.

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

desktop-client/tray.js

@@ -14,13 +14,20 @@ const TRAY_ICON_BASE64 =
   'PB7S4/EuoISgYrLKD1dOhOPFP6+4R7ieoQPNv9/ULZ+zfis+0Y1e+F7oF3H5F+Xt' +
   'T5p0AqBYeEeEF8k/gtcS56z6f/E5UOLHL8A8a4yC0IHbH4AAAAASUVORK5CYII=';
 
+/**
+ * @param {Object} options
+ * @param {number} options.port
+ * @param {() => void} options.onShow
+ * @param {() => void} options.onQuit
+ * @returns {{ update: (info: { title: string|null, artist: string|null }) => void, destroy: () => void }}
+ */
+function createTray({ port, onShow, onQuit }) {
   let trayInstance = null;
-let opts = null;
   let currentTitle = null;
   let currentArtist = null;
 
   function buildMenu() {
-  const url = `http://localhost:${opts.port}/`;
+    const url = `http://localhost:${port}/`;
     const nowPlaying =
       currentTitle && currentArtist
         ? `${currentTitle} — ${currentArtist}`
@@ -30,24 +37,14 @@ function buildMenu() {
       { label: "What's That Music", enabled: false },
       { label: `Now Playing: ${nowPlaying}`, enabled: false },
       { type: 'separator' },
-    { label: 'Show Player', click: () => opts.onShow && opts.onShow() },
+      { label: 'Show Player', click: () => onShow && onShow() },
       { label: 'Open Overlay in Browser', click: () => shell.openExternal(url) },
       { label: 'Copy OBS URL', click: () => clipboard.writeText(url) },
       { type: 'separator' },
-    { label: 'Quit', click: () => opts.onQuit && opts.onQuit() },
+      { label: 'Quit', click: () => onQuit && onQuit() },
     ]);
   }
 
-/**
- * @param {Object} options
- * @param {number} options.port
- * @param {() => void} options.onShow
- * @param {() => void} options.onQuit
- * @returns {{ update: (info: { title: string|null, artist: string|null }) => void, destroy: () => void }}
- */
-function createTray(options) {
-  opts = options;
-
   const icon = nativeImage.createFromDataURL(TRAY_ICON_BASE64);
   icon.setTemplateImage(true);