updated to latest cagent version and added a workflow to create a latest tag on every release of cagent-action

[derekmisler]

Summary

Updates the cagent-action to use the latest cagent version (v1.19.4) and adds automated release management with a new workflow that creates and maintains a "latest" tag for easier consumption by users. This eliminates the need for users to track specific version numbers and ensures they always get the most recent stable release.

Changes

Added

• .github/workflows/release.yml: New GitHub Actions workflow that automatically creates and updates a "latest" tag whenever a new version is released (triggered on v*.*.* tags)

Modified

• action.yml: Updated default cagent version from v1.15.6 to v1.19.4
• README.md: Updated all example usage from @v1.0.4 to @latest and updated default cagent version in documentation
• examples/code-analysis.yml: Updated action reference to use @latest
• security/README.md: Updated action reference to use @latest
• tests/test-job-summary.sh: Updated test expectations to reflect new cagent version v1.19.4

Technical Details

Key changes:

• Release Automation: The new workflow uses git operations to force-update the "latest" tag to point to the newest release, enabling users to reference @latest instead of specific version numbers
• Version Bump: Significant cagent version upgrade from v1.15.6 to v1.19.4, bringing ~4 minor versions of improvements and bug fixes
• Documentation Consistency: All examples and documentation now consistently reference @latest for better user experience

The release workflow includes proper cleanup (deleting existing tags) and uses pinned action versions for security. It runs on Ubuntu latest and requires write permissions to update repository tags.

Testing

• Updated test expectations to match new cagent version
• All documentation examples updated consistently
• Manual testing recommended: Create a test tag to verify workflow execution
• Verify @latest resolves correctly after workflow runs

Breaking Changes

None - this is a backward-compatible update that improves the user experience.

Migration Guide

For existing users:

• No immediate action required - existing version pins (e.g., @v1.0.4) will continue working
• Recommended: Update your workflows to use @latest for automatic updates:

  # Before
  uses: docker/cagent-action@v1.0.4
  
  # After  
  uses: docker/cagent-action@latest

Related Issues

None explicitly referenced

Checklist

• Code follows project style guidelines
• Self-review completed
• Comments added for complex logic (workflow steps documented)
• Documentation updated (README, examples, security docs)
• No new warnings introduced
• Tests updated to reflect version changes
• Security implications considered (pinned action versions, minimal permissions)

[derekmisler]

/describe

[github-actions]

✅ PR description has been generated and updated!