🤖 Spaces can't get permanently stuck anymore when the members holding the
shared key are gone for good. If that happens, newer members now see plainly
what's wrong when inviting ("the members who hold this space's shared key
haven't been online since May…"), and admins get a way out: a "Reset the
shared key" control in the admin console mints a fresh key the next time
anyone opens the app. Resetting is honest about its cost — old profile photos
and member-built apps can't be recovered — and messages are never touched:
chats have their own keys.