docs: add contributing guidelines to CONTRIBUTING.md

[twangodev]

Summary by CodeRabbit

• Documentation
  • Added contributing guidelines documentation to assist contributors.

[coderabbitai]

Caution

Review failed

The pull request is closed.

Walkthrough

A new CONTRIBUTING.md file is added to the repository, containing a "Contributing" header and a reference link to the contributing guidelines. This provides initial documentation structure for contribution instructions.

Changes

Cohort / File(s)	Summary
Documentation CONTRIBUTING.md	New file with "Contributing" header and reference link to contributing guidelines

Estimated code review effort

🎯 1 (Trivial) | ⏱️ ~2 minutes

• No logic or functional code to review
• Single new documentation file with minimal content
• Straightforward addition with no dependencies on existing code

Poem

🐰 A guidebook born, so crisp and neat,
For contributors to greet!
With links and headers, clear as day,
They'll hop along the contribution way. 🌟

✨ Finishing touches

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Post copyable unit tests in a comment
• Commit unit tests in branch chore/contributing

---

📜 Recent review details

Configuration used: CodeRabbit UI

Review profile: CHILL

Plan: Pro

📥 Commits

Reviewing files that changed from the base of the PR and between c37d431 and b61f15f.

📒 Files selected for processing (1)

• CONTRIBUTING.md (1 hunks)

Tip

📝 Customizable high-level summaries are now available in beta!

You can now customize how CodeRabbit generates the high-level summary in your pull requests — including its content, structure, tone, and formatting.

• Provide your own instructions using the high_level_summary_instructions setting.
• Format the summary however you like (bullet lists, tables, multi-section layouts, contributor stats, etc.).
• Use high_level_summary_in_walkthrough to move the summary from the description to the walkthrough section.

Example instruction:

"Divide the high-level summary into five sections:

1. 📝 Description — Summarize the main change in 50–60 words, explaining what was done.
2. 📓 References — List relevant issues, discussions, documentation, or related PRs.
3. 📦 Dependencies & Requirements — Mention any new/updated dependencies, environment variable changes, or configuration updates.
4. 📊 Contributor Summary — Include a Markdown table showing contributions:
   | Contributor | Lines Added | Lines Removed | Files Changed |
5. ✔️ Additional Notes — Add any extra reviewer context.
   Keep each section concise (under 200 words) and use bullet or numbered lists for clarity."

Note: This feature is currently in beta for Pro-tier users, and pricing will be announced later.

---

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

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.

[Copilot]

Pull Request Overview

This PR adds a CONTRIBUTING.md file that directs potential contributors to the project's external contributing guidelines hosted at docs.fish.audio.

• Adds a new CONTRIBUTING.md file with a link to external documentation

---

💡 Add Copilot custom instructions for smarter, more guided reviews. Learn how to get started.