Give each admitted device its own persisted storage credential, and rotate the
presence key and invite code on removal. Persist grants before sending credentials
and reject queued requests after withdrawal. Show pending requests and connected
or offline devices in Live Share; joining can wait for approval or be cancelled.

Raise relay address limits to accommodate the private device rooms behind a
shared network. Full CI, admission and revocation tests, native UI replay, and a
30-guest typing run passed.

Assisted-by: gpt-6.1-sol