docs: add CONTRIBUTING.md and SECURITY.md

[pablozramirez73]

Adds community files to improve contributor onboarding and security reporting.

Changes:

• ✨ CONTRIBUTING.md — contribution guidelines and workflow
• ✨ SECURITY.md — responsible vulnerability disclosure policy

These files help grow the community around the project. 🎉

[Copilot]

Pull request overview

Adds standard GitHub community health files to the repository to improve contributor onboarding and provide a clear security reporting path.

Changes:

• Adds CONTRIBUTING.md with a basic contribution workflow and issue-reporting guidance.
• Adds SECURITY.md describing responsible vulnerability reporting and supported versions policy.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated no comments.

File	Description
CONTRIBUTING.md	Introduces contributor workflow, guidelines, and issue reporting instructions.
SECURITY.md	Documents vulnerability reporting channels and a supported versions statement.

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