What posts where
Celebration posts are public-safe; organizer alerts are for organizers only.
Celebrations channel gets exactly one message type: "🎉 Today we celebrated Maria's birthday — 11 teammates signed her card!" — posted only after delivery, so the surprise survives. You can switch this post off per campaign (recommended for sensitive occasions).
Organizers channel hears: a card opened for signing, the final-call summary, cards held for your review, content-watch flags, teammate reports, replies awaiting your OK, and join-link sign-ups needing approval — each with a button to the right page.