Add Harness Handbook paper to papers catalogue

[natnew]

Motivation

• Agent harnesses distribute behaviour across prompts, state management, tool integrations, and middleware, which makes security-focused review and change-impact analysis difficult.
• The paper documents a behaviour-to-code mapping and progressive-disclosure workflow that improves inspectability and helps reviewers locate implementation sites for behavioural changes.

Description

• Added a neutral metadata entry for "Harness Handbook: Making Evolving Agent Harnesses Readable, Navigable, And Editable" to resources/papers.md with canonical arXiv link and caveat about security integration.
• Added a required resource-quality scoresheet under rubrics/scoresheets/resource-harness-handbook.md with a reviewed verdict of "Include with reviewer-noted caveats" and an 11/15 aggregate.
• The entry is placed in the existing papers catalogue without creating new sections and follows the repository's metadata and editorial conventions.
• Codex was used to read the contributing guidelines, inspect the catalogue format, verify the arXiv record, draft the neutral resource entry, and generate the resource-quality scoresheet.

Testing

• git diff --check passed with no repository formatting errors reported.
• Attempted mkdocs build --strict and dependency installation but the run failed due to external package registry/network access errors (environmental 403), not repository content errors.
• Attempts to run markdownlint and markdown-link-check (and npx markdownlint-cli) were blocked by missing tools or npm registry access (403), so local link/lint checks could not complete in this environment.
• All test failures are environmental (tooling/network access) and not due to the documentation changes themselves, and the PR includes only documentation and a scoresheet so CI in the project should validate markdown and links on the platform when the PR is opened.

---

Codex Task

[natnew]

@copilot resolve the merge conflicts in this pull request

[Copilot]

@copilot resolve the merge conflicts in this pull request

Resolved. The only conflict was in resources/papers.md where main had added a new BlindGuard entry in the same location. Both entries are now included — the Harness Handbook entry from this branch and the BlindGuard entry from main. The merge commit is 0928cc3.