chore: add CodeRabbit review configuration

[major]

Summary

• Add .coderabbit.yaml with chill review profile and path-specific instructions for the Perl source, tests, templates, and CI workflows.
• Auto-review is disabled so CodeRabbit only runs on-demand, not on every push.

Changes

• New .coderabbit.yaml with path instructions covering mysqltuner.pl, build/, tests/, templates/, workflows, Makefile, and Dockerfile
• Knowledge base configured to read AGENTS.md for project context

Testing

• Config validates (CodeRabbit CLI ran successfully against this branch)

Summary by CodeRabbit

• Chores
  • Added configuration for automated code review tool setup including review customization, pre-merge verification, selective filtering, and knowledge base configuration.

[coderabbitai]

Caution

Review failed

The pull request is closed.

Warning

Ignoring CodeRabbit configuration file changes. For security, only the configuration from the base branch is applied for open source repositories.

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: defaults

Review profile: CHILL

Plan: Pro

Run ID: 5c56fbc1-bd72-405a-86f8-b0df67edbf2c

📥 Commits

Reviewing files that changed from the base of the PR and between 7bc24d8 and 0580272.

📒 Files selected for processing (1)

• .coderabbit.yaml

---

📝 Walkthrough

Walkthrough

A new .coderabbit.yaml configuration file establishes CodeRabbit's review behavior for the MySQLTuner repository. It sets review language and tone, configures pre-merge checks and auto-review policy, defines path-specific review instructions for Perl scripts, build files, tests, and deployment configs, and enables chat automation with knowledge base integration.

Changes

CodeRabbit Configuration

Layer / File(s)	Summary
Core review workflow settings .coderabbit.yaml	Top-level settings establish English language, reviewer tone/instructions, and core workflow toggles (abort-on-close, review status visibility, suggested labels/reviewers behavior).
Pre-merge checks and auto-review policy .coderabbit.yaml	Pre-merge check configuration with branch targeting and title keyword rules; auto-review is disabled to require explicit requests.
Path-specific review guidance .coderabbit.yaml	Per-path review instructions for the Perl main script (CVE/CSV output expectations), build scripts, tests (validation checks), templates, GitHub workflows (security focus), Makefile, and Dockerfile (syntax verification).
Chat and knowledge base configuration .coderabbit.yaml	Auto chat replies are enabled and a global knowledge base scope is configured with guideline file pattern matching.

Estimated code review effort

🎯 2 (Simple) | ⏱️ ~10 minutes

Poem

🐰 A config so fine, now CodeRabbit knows,
Where to review, what guidance each path owes,
Perl scripts and tests, with instructions so clear,
This .coderabbit.yaml brings order here! 🎯✨

✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch chore/add-coderabbit-config

---

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

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