Add on-demand GitHub release workflow

[buddingengineers12345]

Summary

• Adds an on-demand Release GitHub Actions workflow to bump the repo version, tag, and create a GitHub Release.
• Introduces scripts/bump_version.py to update [project].version in pyproject.toml.

How to use

• Run the Release workflow via Actions → Release → Run workflow.
• Provide either:
  • bump: patch / minor / major, or
  • version: explicit X.Y.Z (overrides bump)
• Optionally set prerelease: true to mark the GitHub Release as a prerelease.

Notes

• The workflow commits the version bump to the default branch, tags it as vX.Y.Z, pushes the commit+tag, and creates a GitHub Release with autogenerated notes.