* feat: Add web-based UI for fair random number generator with multi-language support and live demo link in README
* feat: Add mode switching (Fair/Pure Random), repeat detection, and cryptographic randomness for web app
* - Add "Pure Random" mode with repeat detection feature
- Improve UI layout and styling for compact presentation screens
- Introduce auto cleanup of existing processes on port 80 before startup
- Update translations and language toggle functionalities
- Remove unused test dependencies
- Add Apache 2.0 license and update relevant metadata
* fix: Update number pooling logic and adjust test for remaining count
- Replace Flask with FastAPI for improved performance and modern architecture
- Add exhaustive test coverage for language toggle, range settings, and functionality validations
- Ensure app instance uniqueness with process checking logic
- Update dependency management and improve repository state for FastAPI compatibility
