#14: Gitea CI, registry composes, Node 22 image and changelog

- Gitea Actions: Trivy, Vitest in a Dockerfile test stage, arm64 image build, image
  scan and smoke test; releases reuse the image by content hash.
- docker-compose.<edition>.registry.yaml run the stack from the published image.
- Dockerfile: Node 22, a test stage, and no npm in the runtime image.
- README, CLAUDE.md and CHANGELOG describe the CI, the image and the release flow.

Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>

.dockerignore

@@ -1,7 +1,11 @@
 node_modules
 .git
+.gitea
+.gitattributes
 .env
-test
+.env.*
+!.env.example
 *.md
 coverage
 src/public/assets/mc
+.superpowers