Fixes two rough edges from first use:
- The "Add to playlist" dialog blocked on the relay publish before closing, so it
felt stuck / "didn't close, just reset". Now it closes IMMEDIATELY on Save and
publishes in the background; the result comes back as a toast (optimistic, like
the feed insert). No more waiting on the relay round-trip with the modal open.
- After adding/creating a playlist you had to hard-refresh to see it. The picker
now dispatches `bitvid:playlists-changed`, and channelPlaylists.js listens for
it (matching the current channel) and re-fetches — immediately and again after
~2s to cover relay propagation lag — so the section updates on its own.
Syntax + lint + build clean.
Co-Authored-By: Claude Opus 4.8 <[email protected]>
