BOOTSTRAP_ADMIN_EMAIL/PASSWORD seed a role=admin account at boot if absent —
the only way to get the first admin, since /register makes plain users and
promotion needs an existing admin. Idempotent and race-safe. Tests included.
- delete api/requests.http and ARCHITECTURE.md (coordinator content)
- rewrite README.md and .env.example for the userservice
- drop dead RunPeriodic (reaper machinery userservice has no use for)
- fix .gitignore/.dockerignore/.golangci.yml module + artifact names
- degeneralize stale copied comments that said "coordinator"