Replace DCO requirement with Contributor License Agreement

[mayankpande88]

Description

This change replaces the Developer Certificate of Origin (DCO) sign-off requirement with a Contributor License Agreement (CLA) process. The DCO check has been removed from CI, and all documentation has been updated to reflect the new CLA requirement.

Type of change

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Enhancement (non-breaking change which improves existing functionality)
• Refactor (non-breaking change which improves code structure)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Documentation
• CI/CD

Changes Made

• Removed the dco job from the CI workflow (.github/workflows/ci.yml)
• Updated CONTRIBUTING.md to replace DCO sign-off instructions with CLA information
• Updated the PR template checklist to reference CLA signing instead of DCO
• Updated README.md to reference the CLA requirement instead of DCO

How Has This Been Tested?

• CI workflow syntax is valid
• Documentation changes are consistent across all files

Checklist

• CLA signed (the CLA bot will prompt on your first PR)
• make validate passes (fmt + lint + test)
• Docs updated if the wire shape, config surface, or proxy module behavior changed

https://claude.ai/code/session_01Btcf1vt615aUU2f2Aq7VT5

[cla-assistant]

Thank you for your submission! We really appreciate it. Like many open source projects, we ask that you sign our Contributor License Agreement before we can accept your contribution.
_{You have signed the CLA already but the status is still pending? Let us recheck it.}

[cla-assistant]

Thank you for your submission! We really appreciate it. Like many open source projects, we ask that you sign our Contributor License Agreement before we can accept your contribution.
_{You have signed the CLA already but the status is still pending? Let us recheck it.}

[gemini-code-assist]

Code Review

This pull request replaces the Developer Certificate of Origin (DCO) sign-off requirement with a Contributor License Agreement (CLA) requirement across the repository's documentation, including the pull request template, contributing guidelines, and README. I have no feedback to provide.