Add CODE_OF_CONDUCT.md

[jlaneve]

Summary

Add a code of conduct file to establish community standards for the open-source project.

Why

• Sets expectations for respectful interaction
• Required by many organizations before contributing
• Shows commitment to inclusive community

Recommendation

Adopt the Contributor Covenant v2.1, which is the most widely used code of conduct for open-source projects.

Implementation

1. Copy the Contributor Covenant template
2. Fill in contact method for reporting violations
3. Add link from README.md

Priority

Medium - Standard practice for open-source projects

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From PR #24 open-source readiness review

[jlaneve]

Added in branch docs/code-of-conduct (commit b0e14ba)