Add CODE_OF_CONDUCT.md to reach 100% community health score

[FernandoCelmer]

Description

The repository's GitHub community health score is 75/100. The only missing item is a CODE_OF_CONDUCT.md file. Adding it would bring the score to 100%.

Current Community Health

Item	Status
LICENSE (MIT)	✅
README.md	✅
CONTRIBUTING.md	✅
Pull Request template	✅
Issue templates	✅
CODE_OF_CONDUCT.md	❌ Missing

Implementation

Add a CODE_OF_CONDUCT.md to the repository root. The most widely adopted option is the Contributor Covenant v2.1:

# Contributor Covenant Code of Conduct

## Our Pledge
We as members, contributors, and leaders pledge to make participation
in our community a harassment-free experience for everyone...

Full template: https://www.contributor-covenant.org/version/2/1/code_of_conduct/

Why This Matters

• Signals a welcoming and professional open-source project
• Required by many organizations before they can contribute to or adopt a project
• GitHub surfaces this in the community health checklist that potential contributors see
• Takes 5 minutes to add but improves perceived project maturity

Acceptance Criteria

• CODE_OF_CONDUCT.md exists in repository root
• Uses Contributor Covenant v2.1 (or equivalent)
• Contact method specified for reporting violations
• GitHub community health score reaches 100%