Open Tabletop 0.21.1

Upgrade notes

• From 0.21.0, pull the updated image and recreate the app container. No new migration,
  dependency, environment variable or Compose change is required. Existing accounts and
  passwords are unchanged. Earlier versions must also follow the 0.21.0 upgrade instructions.
• Automated checks passed: 933 tests in npm run check and 25 PostgreSQL integration tests.
  Live Dockhand update verification remains pending.

Fixed

• Startup skips all bootstrap administrator settings and password-file access when any user
  exists, so Docker updates that lose the first-boot file no longer block established installs.
  Empty databases retain credential validation and transactional provisioning protection.

Documentation

• Added separate implementation plans for demo-only 15-dice limits and shared roll
  cooldowns, and full-app room worker process isolation. Plans include regression and
  performance gates, ownership/routing safeguards, deployment and rollback. No runtime
  behavior changed; architecture and reference navigation distinguish plans from contracts.