docs: root CONTRIBUTING.adoc — satisfy the estate docs gate

[hyperpolymath]

Why

The estate docs gate (hyperpolymath/standards scripts/check-docs-presence.sh, run by the Governance reusable pinned in this repo's governance.yml) requires CONTRIBUTING at the repository root: CONTRIBUTING.md | CONTRIBUTING.adoc | 3-practice/CONTRIBUTING.adoc. Its grace cutoff (2026-08-21) has armed, so Governance / Code quality + docs fails without it.

What this is

One file: root CONTRIBUTING.adoc, following the estate norm — the gate's own blast-radius measurement found root CONTRIBUTING.adoc is what the estate actually uses (32 of 40 sampled repos). Content covers setup (this repo's Justfile), branch naming, and Conventional Commits per estate conventions. Nothing else is touched.

Witness (local)

check-docs-presence.sh . → ✅ Core documentation present (README, LICENSE, CONTRIBUTING) (was ::error::Missing required documentation: CONTRIBUTING).

Part of the estate-wide CONTRIBUTING wave (224 repos measured gate-red); one repo, one file, one PR.

[coderabbitai]

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: 89b3bf39-d35e-4b9b-8d58-04ae8cfac359

📥 Commits

Reviewing files that changed from the base of the PR and between 805d674 and d3deb78.

📒 Files selected for processing (1)

• CONTRIBUTING.adoc

Included review availability: 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: scan / shell-secrets
• GitHub Check: scan / gitleaks
• GitHub Check: governance / Security policy checks
• GitHub Check: scan / rust-secrets
• GitHub Check: governance / Well-Known (RFC 9116 + RSR)
• GitHub Check: governance / Code quality + docs
• GitHub Check: governance / Licence consistency
• GitHub Check: governance / Trusted-base reduction policy
• GitHub Check: governance / Guix primary / Nix fallback policy
• GitHub Check: governance / Language / package anti-pattern policy
• GitHub Check: governance / Workflow security linter
• GitHub Check: governance / Check Workflow Staleness
• GitHub Check: scan / Hypatia Neurosymbolic Analysis
• GitHub Check: analyze (actions, none)
• GitHub Check: Empty-linter (invisible characters)
• GitHub Check: Groove manifest check
• GitHub Check: Validate A2ML manifests
• GitHub Check: test (1.11)
• GitHub Check: test (1.10)
• GitHub Check: Validate K9 contracts
• GitHub Check: test (1.11)
• GitHub Check: test (1.10)

🔇 Additional comments (1)

CONTRIBUTING.adoc (1)

1-58: LGTM!

---

📝 Summary

Summary by CodeRabbit

• Documentation
  • Added a contribution guide covering local development, issue reporting, branch naming, and commit message conventions.
  • Documented repository contribution practices and the role of the root-level guide.

Walkthrough

The pull request adds a root-level CONTRIBUTING.adoc guide. It documents repository conventions, local development with the Justfile, issue reporting, branch naming, Conventional Commits, and the estate documentation requirement.

Changes

Contribution guide

Layer / File(s)	Summary
Contribution guidance CONTRIBUTING.adoc	Adds guidance for AsciiDoc, Conventional Commits, integration tests, local setup, issue reports, branch names, commit messages, and the root-document requirement.

Priority: ⬇️ Low

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

Change: Other

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Description check	✅ Passed	The description clearly explains the addition of the root CONTRIBUTING.adoc file and its purpose in satisfying the estate documentation gate.
Title check	✅ Passed	The title clearly identifies the documentation change and its purpose. It is concise and specific.
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.

---

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 reads the guide,
Commands sit neat inside.
Branches follow clear tracks,
Commits wear tidy tags.
The estate gate stands wide,
And carrots wait beside.}

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