fix(desktop): mute hidden link-title window so historical links don't autoplay audio

Tier-2 link-title resolution loads the URL in an offscreen BrowserWindow to
read its <title> when curl can't. That window was never muted, so pages that
autoplay media (e.g. YouTube `watch` URLs) leaked ~2s of audio every time a
session containing such links was re-rendered. Move the window creation into a
dedicated helper that calls `webContents.setAudioMuted(true)` immediately after
construction, so the offscreen probe can never emit sound.

Fixes #49505

apps/desktop/electron/link-title-window.cjs

@@ -0,0 +1,42 @@
+'use strict'
+
+// Hidden BrowserWindow used by tier-2 link-title resolution: when curl can't
+// read a page <title> (bot walls, JS-rendered pages), we briefly load the URL
+// in an offscreen window and read its title. That window loads arbitrary
+// user-linked pages — including YouTube/`watch` URLs that autoplay — so it must
+// never be allowed to emit sound.
+
+function linkTitleWindowOptions(partitionSession) {
+  return {
+    show: false,
+    width: 1280,
+    height: 800,
+    webPreferences: {
+      backgroundThrottling: false,
+      contextIsolation: true,
+      javascript: true,
+      nodeIntegration: false,
+      sandbox: true,
+      session: partitionSession,
+      webSecurity: true
+    }
+  }
+}
+
+// Create the offscreen title-fetch window and immediately mute it. Without the
+// mute, autoplaying media on the loaded page (e.g. a YouTube link) leaks ~2s of
+// audio every time a session containing such links is re-rendered. See #49505.
+function createLinkTitleWindow(BrowserWindow, partitionSession) {
+  const window = new BrowserWindow(linkTitleWindowOptions(partitionSession))
+
+  try {
+    window.webContents.setAudioMuted(true)
+  } catch {
+    // webContents may be unavailable in degraded/headless environments; muting
+    // is best-effort and the window is destroyed within a few seconds anyway.
+  }
+
+  return window
+}
+
+module.exports = { createLinkTitleWindow, linkTitleWindowOptions }

apps/desktop/electron/main.cjs

@@ -34,6 +34,7 @@ const {
   SESSION_WINDOW_MIN_WIDTH
 } = require('./session-windows.cjs')
 const { canImportHermesCli, verifyHermesCli } = require('./backend-probes.cjs')
+const { createLinkTitleWindow } = require('./link-title-window.cjs')
 const { probeGatewayWebSocket } = require('./gateway-ws-probe.cjs')
 const { adoptServedDashboardToken } = require('./dashboard-token.cjs')
 const { waitForDashboardPort } = require('./backend-ready.cjs')
@@ -2980,20 +2981,7 @@ function runRenderTitleJob(rawUrl) {
     }
 
     try {
-      window = new BrowserWindow({
-        show: false,
-        width: 1280,
-        height: 800,
-        webPreferences: {
-          backgroundThrottling: false,
-          contextIsolation: true,
-          javascript: true,
-          nodeIntegration: false,
-          sandbox: true,
-          session: partitionSession,
-          webSecurity: true
-        }
-      })
+      window = createLinkTitleWindow(BrowserWindow, partitionSession)
     } catch {
       return finish('')
     }