Refactor frontend components and integrate Mantine UI for improved user experience

Commit notes

- Replaced Radix UI components with Mantine UI components across the application, enhancing the visual consistency and usability. - Updated the pnpm lockfile to reflect new dependencies for Mantine. - Refactored various components, including AuthSection, AccountPopover, and TransportControls, to utilize Mantine's design system. - Removed unused Radix UI components and styles, streamlining the codebase. - Enhanced the layout and routing structure for better navigation and responsiveness. - Improved user notifications and error handling within the AuthProvider for a more intuitive user experience.