Update to Sandcastles

{
  "description": "Add channels to your watchlist",
  "included_files": [],
  "name": "channels-add",
  "skill_md_contents": "---\nname: channels-add\ndescription: Add channels to your watchlist\n---\nAdd this channel (or these channels) to my watchlist: $ARGUMENTS\n\nUse the `add_channels_to_watchlist` tool. Pass `$ARGUMENTS` as the channel identifier(s) — accepts UUIDs, handles, URLs, or a list of any combination. Report back which channels were added, which were submitted as new to Sandcastles (and that scraping is in progress), and which were skipped (with the reason). If `$ARGUMENTS` is empty, ask the user which channel(s) they want to add.\n"
}