Project nested publication pull request URL

[chubes4]

Summary

• project docs_agent_publication from metadata.runner_workspace_publication.pull_request.url
• update reusable workflow source, runner recipes, runtime-result fixture, and deterministic contract assertions together
• preserve the existing output name and required behavior

Fixes #162.

How to test

1. Check out WP Codebox v0.12.27 at 65cc5fb4699cb7c2df13d04b4715c97097ac7565.
2. Run php tests/validate-docs-agent-packages.php.
3. Run php tests/validate-external-native-package-sources.php.
4. Run WP_CODEBOX_DIR=/path/to/wp-codebox php tests/validate-wp-codebox-run-agent-task-contract.php.
5. Run actionlint .github/workflows/maintain-docs.yml.
6. Run php -l tests/validate-wp-codebox-run-agent-task-contract.php.
7. Run git diff --check origin/main...HEAD.

All commands pass locally.

Compatibility

The docs_agent_publication output name and required behavior are unchanged. Its path now follows the producer-owned v1 publication result shape, correcting a projection that could not resolve. No extension-path impact.

Source evidence

• https://github.com/Automattic/build-with-wordpress/actions/runs/29663992711
• Correct developer workflow provenance documentation build-with-wordpress#121

AI assistance

• AI assistance: Yes
• Tool(s): OpenCode with OpenAI GPT-5.6 Sol
• Used for: Diagnosed the result-shape mismatch, updated workflow and fixtures, added deterministic contract coverage, and ran verification. Chris reviewed and owns the change.