v1.21.0

What's Changed

• Set output as background by @christian-byrne in #3079
• [feat] Add file upload support to canvas background image setting by @christian-byrne in #3958
• Trigger browser test expectations update by @christian-byrne in #3959
• [3d] performance improve by @jtydhr88 in #3961
• [Feature] Add audio preview support to queue sidebar by @christian-byrne in #3954
• [Dev Tool] Add claude directives by @christian-byrne in #3960
• Move user.css to user data by @christian-byrne in #3952
• [fix] Make gallery navigation buttons visible on mobile devices by @christian-byrne in #3953
• 1.21.0 by @comfy-pr-bot in #3962

Full Changelog: v1.20.4...v1.21.0