api-v0.1.0

ci: publish beyond-objects image to ghcr + fix release-api perms (#7)

- Dockerfile: build+run on ubuntu:24.04 (noble) to match the prod rootfs; slim.
- release-image.yml: tag-triggered (api-v*), native amd64+arm64, push-by-digest +
  multi-arch manifest -> ghcr.io/beyondoss/beyond-objects. Latest action versions.
- release-api.yml: add 'permissions: contents: write' (the release upload needs it;
  mirrors auth/release-server.yml) and bump checkout@v7 + action-gh-release@v3.
- Formatted with the repo's dprint config so check:fmt passes.

Co-authored-by: Claude Opus 4.8 (1M context) <noreply@anthropic.com>