#164 · SimpleX dormant-member tracking !dormant + hourly auto-removal scheduler

Context

Signal tracks inactivity tiers and auto-removes 90+-day-silent members hourly. SimpleX has neither.

Acceptance criteria

• [ ] !dormant (admin) shows activity-tier summary; !dormant <days> lists N+-day-inactive members; !dormant lurkers lists zero-engagement.
• [ ] A new scheduler auto-removes members past a configurable threshold and logs each removal.
• [ ] Registered in index.ts and stopped on shutdown; no-ops if disabled.

Technical hints

• Signal reference: commands/admin/dormant-members.command.ts + scheduler/dormant-removal-scheduler.ts.
• SimpleX target: commands/admin/dormant.command.ts + scheduler/dormant-removal-scheduler.ts.
• Derive activity from the bot's own bot_command_usage / simplex_messages (Postgres, persistent) — the SimpleX chat DB is ephemeral and resets on restart.

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