getActiveRoomSessionSnapshot() caches the frozen snapshot keyed on the session
reference, but RoomDataHandler (tradeMode/groupId/isGuildRoom/doorMode/allowPets)
and RoomPermissionsHandler (controllerLevel/owner) mutate those fields on the
same session object without invalidating the cache. Any consumer reading a
mutable field via useActiveRoomSessionSnapshot would get stale data and never
re-render.
Expose invalidateRoomSessionSnapshot() on IRoomHandlerListener and call it from
both handlers after they mutate the session.