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.

If the file already had its own signing section, that section is replaced in place instead of adding a second one. Lines elsewhere that told people to sign with GPG are changed to match the policy (SSH for people).

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

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ℹ️ Recent review info

⚙️ Run configuration

Configuration used: Organization UI

Review profile: ASSERTIVE

Plan: Advanced

Run ID: 4f451259-7244-4abd-a58a-a51c867748e5

📥 Commits

Reviewing files that changed from the base of the PR and between 67f7d50 and 984e813.

📒 Files selected for processing (1)

• CONTRIBUTING.adoc

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. (22)

• GitHub Check: governance / Exemption ratchet
• GitHub Check: governance / Guix packaging policy (Nix retired)
• GitHub Check: governance / Security policy checks
• GitHub Check: governance / Trusted-base reduction policy
• GitHub Check: governance / Well-Known (RFC 9116 + RSR)
• GitHub Check: governance / Live Actions policy (credentialed advisory)
• GitHub Check: governance / Allowlist Preflight
• GitHub Check: governance / Debt ratchet
• GitHub Check: governance / Actions lockfile verify
• GitHub Check: governance / Workflow security linter
• GitHub Check: governance / Language / package anti-pattern policy
• GitHub Check: governance / Licence consistency
• GitHub Check: governance / Code quality + docs
• GitHub Check: governance / Check Workflow Staleness
• GitHub Check: hypatia / Hypatia Neurosymbolic Analysis
• GitHub Check: actions.lock is in sync with the workflow YAML
• GitHub Check: Validate DEED manifests
• GitHub Check: Empty-linter (invisible characters)
• GitHub Check: Groove manifest check
• GitHub Check: Validate K9 contracts
• GitHub Check: Analyze (actions)
• GitHub Check: semgrep-cloud-platform/scan

⚠️ CI failures not shown inline (2)

GitHub Actions: Lock Sync Gate / 0_actions.lock is in sync with the workflow YAML.txt: docs: add Signed commits section to CONTRIBUTING

Conclusion: failure

View job details

##[group]Run set -euo pipefail
 �[36;1mset -euo pipefail�[0m
 �[36;1m# The checker is taken from the BASE commit, never from the pull�[0m
 �[36;1m# request's own tree, so a PR cannot weaken the gate that judges it.�[0m
 �[36;1m#�[0m
 �[36;1m# Exception, and only this one: on the PR that FIRST introduces the�[0m
 �[36;1m# checker the base has no copy of it, so the base-only form can never�[0m
 �[36;1m# pass. Fall back to the head copy in that case alone -- there is no�[0m
 �[36;1m# base version for the head to be weaker than, so the anti-tamper�[0m
 �[36;1m# property is not what is being given up. Absent from both is a hard�[0m
 �[36;1m# failure, never a skip.�[0m
 �[36;1mif git cat-file -e "${BASE_SHA}:scripts/check-lock-sync.sh" 2>/dev/null; then�[0m
 �[36;1m  git show "${BASE_SHA}:scripts/check-lock-sync.sh" > "${RUNNER_TEMP}/check-lock-sync.sh"�[0m
 �[36;1m  echo "checker: base ${BASE_SHA}"�[0m
 �[36;1melse�[0m
 �[36;1m  test -f scripts/check-lock-sync.sh \�[0m
 �[36;1m    || { echo "::error::scripts/check-lock-sync.sh is absent from BOTH base and head"; exit 1; }�[0m

---

GitHub Actions: Lock Sync Gate / actions.lock is in sync with the workflow YAML: docs: add Signed commits section to CONTRIBUTING

Conclusion: failure

View job details

##[group]Run set -euo pipefail
 �[36;1mset -euo pipefail�[0m
 �[36;1m# The checker is taken from the BASE commit, never from the pull�[0m
 �[36;1m# request's own tree, so a PR cannot weaken the gate that judges it.�[0m
 �[36;1m#�[0m
 �[36;1m# Exception, and only this one: on the PR that FIRST introduces the�[0m
 �[36;1m# checker the base has no copy of it, so the base-only form can never�[0m
 �[36;1m# pass. Fall back to the head copy in that case alone -- there is no�[0m
 �[36;1m# base version for the head to be weaker than, so the anti-tamper�[0m
 �[36;1m# property is not what is being given up. Absent from both is a hard�[0m
 �[36;1m# failure, never a skip.�[0m
 �[36;1mif git cat-file -e "${BASE_SHA}:scripts/check-lock-sync.sh" 2>/dev/null; then�[0m
 �[36;1m  git show "${BASE_SHA}:scripts/check-lock-sync.sh" > "${RUNNER_TEMP}/check-lock-sync.sh"�[0m
 �[36;1m  echo "checker: base ${BASE_SHA}"�[0m
 �[36;1melse�[0m
 �[36;1m  test -f scripts/check-lock-sync.sh \�[0m
 �[36;1m    || { echo "::error::scripts/check-lock-sync.sh is absent from BOTH base and head"; exit 1; }�[0m

🔇 Additional comments (1)

CONTRIBUTING.adoc (1)

112-127: LGTM!

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📝 Summary

Summary by CodeRabbit

• Documentation
  • Added contribution guidance requiring signed commits on the default branch and explaining how people, automated tools and workflows should sign or submit changes.
  • Clarified that pull requests must be squash-merged, unsigned commits block merging, and rebase merging is unavailable.

Walkthrough

The contribution guide adds signed-commit requirements for people, interactive agents, apps, bots, and workflows. It also states that pull requests must use squash merges and that unsigned commits block merging.

Changes

Signed Commit Policy

Layer / File(s)	Summary
Commit signing and merge requirements CONTRIBUTING.adoc	The guide sets signing requirements for commits, including SSH signing keys and verified committer email. It directs apps, bots, and workflows to use GitHub’s API or the estate signed-push action. It also describes pull request commit checks, squash merges, and the stated restriction on rebase merges.

Priority: ⬇️ Low

Estimated code review effort: 1 (Trivial) | ~3 minutes

Change: Other

Merge Risk: ⚪ Minimal · up to 984e8

The guide clarifies signing and squash-merge expectations. No concrete issue is established that should block merging.

Security Architecture Review

Security architecture risk: ⚪ Minimal · up to 984e8

This documentation-only change clarifies signing responsibilities and squash-merge requirements without changing permissions or enforcement mechanisms. No introduced or worsened security risk was identified. Live repository settings were not independently verified.

Retained concerns
No architecture-level concerns identified.

Security review details

Security Blast Radius

• inferred — The documented policy addresses contributors and commits reaching this repository’s default branch. The changed surface does not add credentials, grant privileges, or extend runtime exposure to other services or data stores.

Trust Boundaries and Controls

• observed — The guide assigns people and interactive agents SSH signing with a GitHub-registered signing key and verified committer email. Apps, bots, and workflows are directed to platform-mediated signing rather than pushing local commits. This establishes documented responsibilities, not independently verified runtime identity binding.
• observed — The text states that a ruleset rejects unsigned pushes, checks every PR-branch commit, and that rebase merging is disabled. These are assertions about existing platform controls; the available evidence does not verify their live configuration.

Resilience and Maintainability Implications

• observed — For a branch blocked by unsigned commits, the documented recovery is to recreate it with signed cherry-picks and open a new PR, rather than bypass the signing gate. The PR adds this guidance without implementing a new recovery state machine.

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title clearly identifies the main change: adding a Signed commits section to CONTRIBUTING.
Description check	✅ Passed	The description explains the documentation change and its signing-policy context. It is related to the changeset.
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.

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