docs: add Code of Conduct

[zichen0116]

Summary

This PR adds a CODE_OF_CONDUCT.md file to the repository based on the Contributor Covenant v2.1.

Why This Matters

A Code of Conduct helps to:

• Set clear expectations for community behavior
• Provide a safe and welcoming environment for all contributors
• Establish guidelines for resolving conflicts
• Demonstrate commitment to inclusive open-source practices

Changes

• Added CODE_OF_CONDUCT.md with Contributor Covenant v2.1

Checklist

• Code of Conduct follows Contributor Covenant v2.1 standard
• File placed at repository root for visibility
• No existing CODE_OF_CONDUCT.md in repository

[pdillard]

This looks like a solid addition. I especially like that the file was added at the repository root since it makes expectations easy to find for new contributors. I’m still learning more about open-source contribution standards, but using Contributor Covenant v2.1 here seems like a good choice for consistency across projects.

[alexanderkokona]

Good addition. The Contributor Covenant v2.1 is a reasonable baseline, and placing it at the repo root means GitHub will automatically surface it in the community health sidebar. One thing worth verifying: the v2.1 template includes a placeholder for a reporting contact, make sure that's pointing to an address someone actually monitors, since a CoC with no clear enforcement path tends to erode trust rather than build it, pairing this with a GOVERNANCE.md or at minimum a CONTRIBUTING.md that references the CoC would round out the community health picture. Clean, low-friction improvement overall.

[Smi15127]

Thank you adding this. It creates a good framework for contributors to know what the standards are. It'll create consistency and professionalism, standardizing all contributions so that anyone working on this are always on the same page and know what the expectations are.

[incrediblemohnish5]

This is a very good initiative to constitutionalize rules for community efforts

[federicobartoli]

Thanks for the contribution. Cross-checking against the official Contributor Covenant v2.1 source, this is an incomplete adoption of the template:

1. Contact placeholder removed instead of filled in. The official "Enforcement" section reads: "Instances of abusive, harassing, or otherwise unacceptable behavior may be reported to the community leaders responsible for enforcement at [INSERT CONTACT METHOD]." This PR drops the trailing at [INSERT CONTACT METHOD] entirely, leaving the sentence truncated and the document with no actual reporting channel — so reports can't be filed and enforcement isn't possible.

2. "Enforcement Guidelines" section omitted. The official v2.1 has a top-level ## Enforcement Guidelines section with four tiers (Correction → Warning → Temporary Ban → Permanent Ban) defining responses and durations. This PR drops the section entirely, which leaves enforcement actions undefined.

3. Maintainer commitment. Adopting a CoC implies someone is on the hook for receiving and acting on reports. Worth confirming with the maintainer that this is desired and that they (or a designated person) accept reports before merging — otherwise this is a doc promising a process the project doesn't run.

Suggest: fill in the contact method, restore the ## Enforcement Guidelines section verbatim from the upstream template, and get maintainer sign-off.