Align repository with llm-d repo template (14 items)

Summary

This repository does not fully conform to the llm-d repo template. The following items should be added to maintain consistency across the organization.

Checklist

Governance Documents

• Add CODE_OF_CONDUCT.md
• Add LICENSE (Apache 2.0)
• Add PR_SIGNOFF.md
• Add SECURITY.md

Linting / Config

• Add .prowlabels.yaml
• Add .yamllint.yml
• Add _typos.toml
• Add pyproject.toml (pre-commit config)

GitHub Metadata

• Add .github/CODEOWNERS
• Add .github/PULL_REQUEST_TEMPLATE.md
• Add .github/ISSUE_TEMPLATE/ directory with bug_report.yml, config.yml, and feature_request.yml

Workflows

• Add ci-pr-checks.yaml
• Add ci-release.yaml
• Add ci-signed-commits.yaml
• Add non-main-gatekeeper.yml

Reference

Template repo: https://github.com/llm-d/llm-d-go-template