docs(agents): add a GEMINI.md pointer to the maintained instructions

[hyperpolymath]

Adds a GEMINI.md pointer file to this repository.

Why. An estate-wide census found a large asymmetry in agent-instruction
files: CLAUDE.md was present almost everywhere, GEMINI.md in a handful of
repositories. Any coding agent that looks for GEMINI.md and does not find one
proceeds with no repository-specific instructions at all.

This file is a pointer, not a second copy of the instructions. Duplicating
guidance across per-agent files guarantees the copies drift. The pointer
redirects to whichever file this repository actually maintains — AGENTS.md
where one exists, otherwise CLAUDE.md — and says to retarget it at
AGENTS.md when one lands.

How this commit was built. The change was made with git plumbing against
origin/<default branch>, not by staging a working tree. The branch contains
exactly one commit adding exactly one file, and carries none of the unrelated
local state present in this checkout. A per-repository assertion required
git diff --name-only <base> <commit> to equal the expected path set exactly,
or the branch was never created.

This PR is opened as a draft on purpose. It is part of a bulk campaign and
is not requesting a merge. Review and merge at your discretion.

🤖 Generated with Claude Code

https://claude.ai/code/session_011eQ7hibx92N7fBDtwgReWk

[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: c3f300d0-dc81-495e-8349-7ab8a8bf219d

📥 Commits

Reviewing files that changed from the base of the PR and between f798b98 and 483bd4e.

📒 Files selected for processing (1)

• GEMINI.md

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. (8)

• GitHub Check: rust-ci / Cargo check + clippy + fmt
• GitHub Check: rust-ci / Cargo audit (security)
• GitHub Check: rust-ci / Coverage (tarpaulin + codecov)
• GitHub Check: scan / gitleaks
• GitHub Check: scan / Hypatia Neurosymbolic Analysis
• GitHub Check: container-build
• GitHub Check: Analyze (actions)
• GitHub Check: Analyze (rust)

🧰 Additional context used

🧠 Learnings (1)

📓 Common learnings

Learnt from: CR
Repo: hyperpolymath/ipv6-only

Timestamp: 2026-09-08T23:46:40.288Z
Learning: Do not duplicate rules here.

🔇 Additional comments (1)

GEMINI.md (1)

1-8: LGTM!

---

📝 Summary

Summary by CodeRabbit

• Documentation
  • Added a guidance document directing coding agents to the repository’s existing instructions.
  • Clarified that instructions should not be duplicated and identified how the guidance should be updated if repository agent instructions are introduced.

Walkthrough

Added GEMINI.md as a pointer to CLAUDE.md. The document excludes Claude Code-specific tooling, prevents duplicated rules, and defines a future switch to AGENTS.md.

Changes

Agent instruction pointer

Layer / File(s)	Summary
Add agent instruction pointer GEMINI.md	Directs coding agents to read CLAUDE.md, skip Claude Code-specific tooling, avoid duplicated rules, and retarget the pointer to AGENTS.md when available.

Priority: ⬇️ Low

Estimated code review effort: 1 (Trivial) | ~2 minutes

Merge Risk: ⚪ Minimal · up to 483bd

This adds GEMINI.md to direct coding agents to the existing repository instructions without changing application behavior or production systems. No current merge-blocking risk is identified.

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
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.
Title check	✅ Passed	The title clearly identifies the addition of a GEMINI.md pointer and accurately reflects the main change.
Description check	✅ Passed	The description explains the purpose, behaviour, scope, and draft status of the GEMINI.md pointer. It is directly related to the changeset.

---

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 found a guide today
It points where coding rules should stay
No copied words hop through the file
Future paths wait in patient style
Bright instructions lead the way}

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

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud