- Home: hide duplicate create/join buttons when user has no groups
- Invite links: /join/group/:id and /join/team/:id pages for one-click joining
- Admin: group admins field, ownership transfer, member management toggle
- Events: new events collection with RSVP (going/interested/maybe) and comments
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
