feat: publish the exact @ekklesia package train to the npm registry (ADR 0053)

Publishes one package release train to the Gitea npm registry under
River_of_Glory_Church, whose packages are publicly readable on purpose:
exactly the .tgz files the package-release gate proved, and nothing else.
Nothing is published by this change.

- scripts/publish-package-train.ts validates the whole local train before
  any request (gate manifest hash, version, revision, unmodified source,
  the nine packages, every artifact's size, SHA-256, integrity,
  SHA256SUMS line, and inner package.json), then publishes in dependency
  order with `npm publish <file.tgz>` under a staging tag. Each package
  is reconciled first (absent: publish; same bytes: accept; other bytes:
  hard stop, version burned), then read back: metadata (name, version,
  integrity, dependency maps, normalized bin, tarball on the registry)
  and the tarball itself, byte for byte, also anonymously. `latest` moves
  only after all nine verify; reruns converge and never delete anything.
  It writes a publication record. The token comes from
  EKKLESIA_PACKAGES_PUBLISH_TOKEN only, through a temporary npm config
  that refers to the variable.
- scripts/test-package-publication.sh proves it against a disposable
  Gitea 1.27.2 with public owners, a publisher team and an outsider:
  anonymous reads, refused unauthorized publishing, byte-identical round
  trips, the registry's own 409, partial-train recovery, the burned
  version hard stop, and dist-tag retry convergence.
- CI: package-release keeps its proven release and hands it on as an
  artifact with its manifest hash; the new package-publication job
  publishes exactly that artifact to the disposable Gitea. Artifact
  actions v3 (node20): v4 refuses any server other than github.com.
- .github/workflows/publish-packages.yml publishes to the real registry
  only by manual dispatch on main, after its own gate run, with the
  secret in the publish step alone.
- docs: the public-read model, the workflow, the record, credentials,
  immutability policy, provider moves, and the first-publication steps.

Co-Authored-By: Claude Opus 5.5 <[email protected]>

docs/development/testing.md

@@ -660,6 +660,13 @@ versions, manifest inspection, release directory, manifest bytes, the pack hook)
 `tests/public-packages.test.ts`, part of `pnpm verify`. See
 [Releases and the public package train](releases.md).
 
+`pnpm test:package-publication` (the CI `package-publication` job, given the `package-release` job's
+artifact) publishes a release train to a disposable Gitea 1.27.2 with Docker, never the real
+registry, and proves the publication tool: byte-identical round trips, anonymous reads, refused
+unauthorized publishing, partial-train recovery, the hard stop on a burned version, and dist-tag
+convergence (`tests/package-publication.integration.ts`). The tool's own rules are unit-tested in
+`tests/package-publication.test.ts`, part of `pnpm verify`.
+
 ## The generic platform image and the reference deployment
 
 These need Docker and build images locally; nothing is pushed or published.