0.2.7

Fixed: a session whose share link was revoked before today opens on the phone again once the daemon reconnects

A session that had a share link stopped rotated its content key, and the relay, which keeps a bounded tail of each session's history, used to trim the rotation frame with everything else after a while. A phone or the dashboard opening such a session fresh had the root key and no way to the current one, so the session never painted. The relay keeps rotation frames from now on; for a session it had already trimmed, the daemon now re-publishes its rotations when it reconnects, told by the relay which ones it lost (Welcome.tail_from), so the chain is whole again and the session opens. Nothing to do: the daemon does it on its next connect after the relay says.