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
