Set up CodeQL scanning

[jbeckwith-oai]

Summary

• add CodeQL analysis for Go and GitHub Actions workflows
• run scans on pushes and pull requests targeting main, without a scheduled cron run
• deny token permissions by default and grant only contents: read and security-events: write to the analysis job
• pin third-party actions to full commit SHAs

Why

This adds automated code scanning so security issues can be detected when changes are pushed or proposed for main.

Validation

• go run github.com/rhysd/actionlint/cmd/actionlint@v1.7.7 .github/workflows/codeql.yml
• YAML parsing
• git diff --cached --check

[github-advanced-security]

You are seeing this message because GitHub Code Scanning has recently been set up for this repository, or this pull request contains the workflow file for the Code Scanning tool.

What Enabling Code Scanning Means:

• The 'Security' tab will display more code scanning analysis results (e.g., for the default branch).
• Depending on your configuration and choice of analysis tool, future pull requests will be annotated with code scanning analysis results.
• You will be able to see the analysis results for the pull request's branch on this overview once the scans have completed and the checks have passed.

For more information about GitHub Code Scanning, check out the documentation.

[HAYDEN-OAI]

looks good to me. the permissions are appropriately scoped, the action refs are pinned, and both new codeql matrix jobs completed successfully. nice addition!