fix: stabilize experimental compile job title

Release v3.1.1

Release v3.1.0

fix: reinstall Hex after setup-beam for OTP 28 compatibility

Refactor CI workflows and update documentation

- Updated Elixir CI workflows across multiple projects to use standardized reusable workflows.
- Enhanced caching strategies in workflows for improved performance.
- Updated LICENSE references in documentation and code to point to the correct file.
- Added new PULL_REQUEST_TEMPLATE for consistent contribution guidelines.
- Removed deprecated CI files to streamline the project structure.