docs: add catalog schema reference

[DevOpsAIguru123]

Summary

• Add docs/catalog-schema.md as the validator-backed catalog schema reference.
• Link it from README, CONTRIBUTING, scoring, and safety docs.
• Record the documentation addition in CHANGELOG.
• Add regression tests that keep the schema reference aligned with validator allowlists for required fields, categories, artifact types, maturity values, and evaluation labels.
• Maintainer refresh on 2026-08-13: extend the schema-reference regression tests to cover all validator enum constants, including action levels, human approval values, and evidence tracing values.
• Maintainer refresh on 2026-08-13: clarify official-vs-community category provenance rules in the schema reference and add a regression test so contributor guidance does not disappear.

Validation

• python3 scripts/sync_readme_counts.py
• python3 scripts/sync_catalog_json.py
• python3 scripts/validate_repos_yaml.py
• /Users/tuximac/projects/awesome-agentic-devops/.venv/bin/python -m pytest -q
• git diff --check

Results on 2026-08-13: README counts in sync, catalog JSON in sync, catalog validation passed for 80 entries, and 158 tests passed.

Risk

Docs and tests only. No catalog entries, credentials, infrastructure, workflow files, or generated counts changed.

Maintainer refresh on 2026-08-12 and 2026-08-13: updated existing daily PR instead of creating a duplicate.

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud