Add a YouTube uploader that follows the existing cookie-based browser
automation pattern (uploader/youtube_uploader + sau youtube CLI:
login/check/upload-video). Supports title/description/tags, thumbnail,
adding to a playlist (for series), and visibility (public/unlisted/private).
Browser automation is used instead of the official Data API on purpose:
videos uploaded by an unaudited API project are force-locked to private
and cannot be made public without Google's compliance audit, which is
impractical for personal/single-channel use. Browser automation has no
such restriction and matches how every other platform here works.
