I think we can support rooms under the standard permission model:
- Can View: View permission allows you to find the room in a browse view and read the room contents.
- Can Join: Join permission allows you to write messages.
- Can Edit: Edit permission is like "moderator/admin" and allows you to retitle the room, change permissions, etc.
For private threads (those missing the `room` flag in T7583), these should all be locked to "members of thread". For rooms, they should have reasonable defaults and be editable in the UI.
- From the column, {nav Dropdown > Edit Room} or similar.
- For Conpherence Full, we can change the last crumb to be a dropdown
We should also figure out how to show room policies to users, since we don't have convenient subheaders like we do for other objects.