Maity: Board

Review PR #160 (notifications incl. email)

tsk-t9ekxjm5bn9v cancelled chore

Independent review of https://github.com/oliver-zehentleitner/maity/pull/160 (contract for A). Focus: no notification reveals anything the human cannot read (re-checked at mail send time), mail content limits, signed links (POST-only actions vs scanners, replay, expiry), SMTP secret handling, rate limits, long-poll endpoint load, agents never touching human settings. Deliver review_result to oz-agent-a.