Major refactor for DevExpress Fluent theme compatibility:
- InfoPanel templates now use strongly-typed context (`InfoPanelContext`)
- Unified grid layout with `MgGridWithInfoPanel` wrapper
- CSS updated to use Fluent theme variables and container queries
- App-wide CSS cleanup and formatting improvements
- `.editorconfig` added for modern CSS support
- Improved InfoPanel instance resolution for nested grids
- Codebase is cleaner, more maintainable, and ready for further customization
