* feat: Add PDM support with auth & i18n enhancements
1. Added PDM project dependency management
- Created pyproject.toml for dependency definitions
- Added PDM lock file for reproducible builds
- Created .pdm-python for virtual environment management
2. Enhanced authentication & configuration
- Added user validation in base configuration
- Implemented streamlit-authenticator for login functionality
- Updated config.example.toml with user authentication fields
3. Improved internationalization (i18n)
- Updated translation files for multiple languages (en, de, pt, vi, zh)
- Enhanced i18n support in the web UI
- Standardized translation structure across language files
