docs: add Signed commits section to CONTRIBUTING

[hyperpolymath]

Adds a Signed commits section to this repo's CONTRIBUTING, per owner ruling D218. The estate policy is docs/SIGNING-POLICY.adoc in hyperpolymath/standards.

This repo's default branch is covered by the zero-bypass Require-Signed-Commits ruleset, and rebase-merge is off. The section tells contributors what that requires:

• People and interactive agents sign with an SSH signing key.
• Apps, bots and workflows write through the API, so GitHub signs their commits.
• PRs are merged with squash.

This is a docs-only change. The commit was created through createCommitOnBranch, so GitHub signs it.

🤖 Generated with Claude Code

https://claude.ai/code/session_01WRvDivYwLSeVCJUrfjic3f

[coderabbitai]

Navigate logical layers of code changes, visualize relationships, and explore their blast radius.

Warning

Review limit reached

You've used all free OSS reviews for now. Wait for the free limit to reset to keep reviewing this public repository.

Next included review available in 25 minutes.

Check out review usage here.

View limit details

Limit details: You’ve used the included review currently available.

Learn how review limits work.

Review configuration:

⚙️ Run configuration

Configuration used: Organization UI

Review profile: ASSERTIVE

Plan: Advanced

Run ID: 8cddf296-64e0-4d79-bbe5-8e73a18ea58c

📥 Commits

Reviewing files that changed from the base of the PR and between 4d38675 and 3b59cca.

📒 Files selected for processing (1)

• .github/CONTRIBUTING.md

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: Organization UI

Review profile: ASSERTIVE

Plan: Advanced

Run ID: 17378228-4b97-48c5-90f6-3ba68a790b47

📥 Commits

Reviewing files that changed from the base of the PR and between f9ee069 and 4d38675.

📒 Files selected for processing (1)

• .github/CONTRIBUTING.md

Included review availability: This review used your included allowance. Your plan provides up to 1 included review per hour; 0 remain after this review.

📜 Recent review details

⏰ Context from checks skipped due to timeout. (15)

• GitHub Check: governance / Licence consistency
• GitHub Check: governance / Code quality + docs
• GitHub Check: governance / Well-Known (RFC 9116 + RSR)
• GitHub Check: governance / Check Workflow Staleness
• GitHub Check: governance / Debt ratchet
• GitHub Check: governance / Exemption ratchet
• GitHub Check: governance / Trusted-base reduction policy
• GitHub Check: governance / Security policy checks
• GitHub Check: governance / Workflow security linter
• GitHub Check: governance / Actions lockfile verify
• GitHub Check: governance / Language / package anti-pattern policy
• GitHub Check: scan / gitleaks
• GitHub Check: hypatia / Hypatia Neurosymbolic Analysis
• GitHub Check: semgrep-cloud-platform/scan
• GitHub Check: Analyze (actions)

🔇 Additional comments (2)

.github/CONTRIBUTING.md (2)

462-463: 🔒 Security & Privacy | 🛡️ Detected with Advanced Tier

Verify the active signed-commit ruleset.

An active Require-Signed-Commits ruleset exists, but the available listing does not show its target branch, signature rule, or bypass actors. Confirm that it applies to the default branch and that no bypass actors can merge unsigned commits.

---

475-475: 🎯 Functional Correctness

The repository setting remains unavailable. The API returned null for allow_rebase_merge, so the documentation claim that rebase-merge is disabled cannot be decided from the supplied evidence.

---

📝 Summary

Summary by CodeRabbit

• Documentation
  • Clarified that commits to the default branch must be signed, with different signing requirements for people, agents, apps and workflows.
  • Documented that pull requests must be squash-merged; unsigned commits block merging, and rebase-merging is unavailable.

Walkthrough

The contribution guide adds a signed-commit policy for commits reaching the default branch. It specifies signing methods, requires squash merges, and describes how unsigned commits on pull request branches affect merging.

Changes

Contribution policy

Layer / File(s)	Summary
Signed commits and merge rules .github/CONTRIBUTING.md	The guide requires signed commits for the default branch and specifies signing methods for people, interactive agents, apps, bots and workflows. It requires squash merges, states that unsigned pull request branch commits block merging, and notes that rebase-merge is disabled.

Priority: ⬇️ Low

Estimated code review effort: 2 (Simple) | ~6 minutes

Change: Other

Suggested reviewers: metadatastician

Merge Risk: ⚪ Minimal · up to 4d386

The contributor guide matches the repository’s signed-commit and merge settings. This documentation change adds no actionable merge risk.

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Description check	✅ Passed	The description accurately explains the documentation change, its signing-policy context, and the repository merge requirements.
Title check	✅ Passed	The title clearly and concisely identifies the addition of a signed-commits section to CONTRIBUTING.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check. Docstring coverage is scoped to functions touched by this diff. Analyzed 0 functions across 0…
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

• Autopilot · Keep fixing CodeRabbit findings and required CI, and resolving merge conflicts

Autopilot is currently an internal CodeRabbit preview.

---

Thanks for using CodeRabbit! It's free for OSS, and your support helps us grow. If you like it, consider giving us a shout-out.

❤️ Share

• X
• Mastodon
• Reddit
• LinkedIn

_{A rabbit signs each commit with care,
Then squash-merges hops through the air.
No unsigned push gets through the gate,
Cherry-picks help reset the state.
The guide keeps every branch in line.}

_{Comment @coderabbitai help to get the list of available commands.}