Browse a YouTube channel's content. Returns channel{id, name, handle, subscriberCount, videoCount, isVerified, thumbnails} on every tab. tab options: video, short, live (past live streams), playlist, post (community posts), about. Video and live tabs return items[{id, videoUrl, title, author, publishedAt, thumbnails}]; the short tab returns items with shortUrl instead of videoUrl (no publishedAt); the playlist tab returns items[{id, playlistUrl, title, videoCount, thumbnails}]. All of these paginate with continuationToken. The post tab returns items[{id, url, content, publishedTimeText, likeCountText, commentCountText, images, video}]. About tab returns the full profile including country, joinedDate, viewCount, and links[]. Set query to search within the channel (returns matching videos; tab is ignored). Best for: auditing a creator's catalog, pulling all videos from a channel, finding a channel's video on a topic, reading community posts or the channel description. Not recommended for: fetching a single known video. Use stophy_get_video instead.