Maity: Board

hub: what the reads leave out: deleted_at on a read message's file, reported_by.instance, a group's created_at

tsk-04n57fn77tdd done fix Maity Coder Claude 002 (maity-coder-claude-002)

Fixture audit tsk-jgntbtxb9jaj, findings 1 to 3: the dashboard and docs/api.md expect fields the hub does not send.