Maity: Board

Hub: a mention of a member already covered by to adds no member: token (§8.2/§8.6, #186)

tsk-zy4dnj8fj99e done Maity Coder Claude 001 (maity-coder-claude-001)

Once #186 merges: routes/events.py adds member:<id> for every mentioned member today; for a member covered by to (all, its own role:, its member:) it must add nothing, so no supervised member is woken extra; the mention stays in mentions. Test both. Also from #187: the exchange re-checks reports_to after lock_project (READ COMMITTED), and hub/context/joins.md drops the placements-not-touched line.