Add GitHub Action to automatically create GitHub releases on version bump

[Copilot]

Description

Adds .github/workflows/create-release.yml — a workflow that automatically creates a GitHub release whenever a push to master introduces a new version that hasn't been tagged yet.

Workflow logic:

• Extracts version from lfpykit/version.py via grep (no exec()/eval())
• Checks for an existing v{version} tag using git ls-remote --exit-code
• If no tag exists, creates a release: tag v{version}, title LFPykit-{version}, with auto-generated notes

Integration with existing workflows:

• The existing python-publish.yml triggers on release: types: [created], so PyPI publishing is automatically chained after this workflow creates the release — no changes to the publish workflow needed.

Related Issue

Closes #[issue]

Motivation and Context

Releases and PyPI publishes were previously manual. With this change, bumping the version in version.py and merging to master is sufficient to trigger the full release pipeline.

How Has This Been Tested

Workflow logic verified by inspection: the git ls-remote --exit-code guard prevents duplicate releases on repeated pushes without a version bump.

Types of changes

• New feature (non-breaking change which adds functionality)
• Docs change / refactoring / dependency upgrade
• Bug fix (non-breaking change which fixes an issue)
• Breaking change (fix or feature that would cause existing functionality to change)

Checklist

• My code follows the code style of this project.
• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• I have read the CONTRIBUTING document.
• I have added tests to cover my changes.
• All new and existing tests passed.