Unread tracking for patches

closed   by alex emery

Issues have count_unread via refs/collab/local/seen/issues/{id} but patches don't. Add equivalent seen-marker tracking for patches so 'patch list' can surface which patches have new activity since the user last looked.

Close reason: Implemented in 6e02a0d — refs/collab/local/seen/patches/{id} seen markers, (N new) in list, mark-seen on show