Agent Skills: integrate-social-auto-upload

Audit, install in an isolated environment, or prepare the `sau` CLI for dreammis/social-auto-upload across Douyin, Kuaishou, Xiaohongshu, and Bilibili. Use only when the user explicitly names social-auto-upload, SAU, or asks for its login, cookie-check, video-upload, note-upload, or scheduled-publishing CLI. Do not trigger for drafting content, generic platform help, or publishing through official browser/API tools.