feat: simplify release workflow by removing PR creation step

[markhallen]

• Rename create-release-pr.yml to create-release.yml
• Remove all PR creation and github-script dependencies
• Implement direct tag creation and push for immediate releases
• Simplify release.yml to only handle tag pushes (remove PR triggers)
• Update README to reflect streamlined "Create Release" workflow

This eliminates GitHub Actions permission issues with PR creation
and provides a faster, more direct release process. The workflow
now creates releases immediately without requiring PR review.

Fixes permission error: "GitHub Actions is not permitted to create
or approve pull requests"

Description

Brief description of the changes in this PR.

Type of Change

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Documentation update
• Refactoring/code cleanup

Testing

• Tests pass locally
• New tests added for new functionality
• Manual testing completed

Checklist

• My code follows the style guidelines of this project
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• My changes generate no new warnings
• Any dependent changes have been merged and published

Additional Notes

Add any additional notes or context about the PR here.