Advance Docs Agent to WP Codebox v0.12.27

[chubes4]

Summary

• advance the reusable Docs Agent workflow and validation checkout to WP Codebox v0.12.27
• record immutable release commit and exact prefixed release asset digests
• declare bounded integrity change evidence and the non-Git snapshot fallback added by Report runner workspace integrity changes wp-codebox#1852

Why

Build with WordPress acceptance run https://github.com/Automattic/build-with-wordpress/actions/runs/29642092608 proves caller verification leaves the intended patch valid but the remaining runtime integrity mismatch is opaque. WP Codebox v0.12.27 preserves bounded changed-path evidence for the diagnostic acceptance replay.

How to test

1. Check out WP Codebox at tag v0.12.27.
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 php tests/repair-docs-links-smoke.php.

Compatibility

• Existing reusable-workflow inputs and outputs are unchanged.
• Publication failures gain bounded path evidence; non-Git workspaces regain bounded snapshot support.

AI assistance

• AI assistance: Yes
• Tool(s): OpenAI GPT-5.6 Sol via OpenCode
• Used for: Advanced immutable release pins and fixtures, documented diagnostic contracts, and ran verification with Chris reviewing and owning the change.