2026.09.0

Added

• Automated release pipeline. Every push to main builds a multi-arch
  (amd64 + arm64) image, pushes it to Docker Hub as :<version>, :<YYYY.MM>
  and :dev, cuts a git tag, and creates a GitHub pre-release with the runnable
  jar and its SHA-256 checksum attached.
• CHANGELOG.md and .claude/rules/10-release.md documenting the CalVer scheme
  and the merge-time changelog obligation.

Changed

• just up / just down now run the prod stack against the published image
  (previously the dev build). The dev stack — Postgres plus a real Artemis
  primary/backup pair, built locally — moved to just dev-up / just dev-down.
  just prod-up / just prod-down are removed.
• just up runs just setup first: it generates deploy/compose/.env with a
  random SECRET_KEY / DB_PASSWORD on first run and pins STUDIO_IMAGE to the
  newest published release tag (:dev until one exists), so a clean clone comes
  up with a single command.
• The published image is sudoit1/artemis-studio on Docker Hub. The previous
  ghcr.io/sudoitir/artemis-studio reference is dropped — CI only ever built that
  tag and threw it away.