Prune stale notifications on read instead of visiting every account

A repository going private or being deleted no longer walks every user's AccountState to delete notifications and digest items about it; every read already filters by current access, and now drops what it hides in the background.

Assisted-by: Crush
taigrrcommitted parent dabbdf9393e128a18a5e191682d3c749ca7849aba5750feBrowse files
4 files changed+54−26

Rendering diff…