Add OCI image labels, issue template config, paths-ignore, and metadata fixes

- Dockerfile: ARG VERSION + OCI labels (title, description, source, licenses, version)
- release.yml: pass VERSION build-arg to all four image builds
- docker-publish.yml: extend paths-ignore to cover community files
- .github/ISSUE_TEMPLATE/config.yml: disable blank issues, link to Discussions and wiki
- README.md: add Getting Help section
- pyproject.toml: expand description; add System Administrators audience classifier

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

.github/workflows/docker-publish.yml

@@ -6,6 +6,10 @@ on:
     paths-ignore:
       - "**.md"
       - "docs/**"
+      - "CONTRIBUTING.md"
+      - "SECURITY.md"
+      - ".github/ISSUE_TEMPLATE/**"
+      - ".github/PULL_REQUEST_TEMPLATE.md"
       - ".github/workflows/release.yml"
       - ".github/workflows/lint.yml"
       - ".github/dependabot.yml"