refactor: replace export options mui components with shadcn components, lessen padding/whitespace

[condyl]

This pull request refactors the ExportOptions component to modernize its UI and reduce dependency on Material UI, switching to custom and third-party UI components for a more consistent design. The help section for using the .ics file is now implemented using a new collapsible pattern and updated icons, with improved styling and structure.

UI framework migration and modernization:

• Replaced Material UI components (Box, ListItemButton, Collapse, Typography, etc.) with custom and third-party components such as Collapsible, Separator, and Lucide icons for a more streamlined and consistent UI.
• Updated the help section to use a new collapsible pattern (Collapsible, CollapsibleTrigger, CollapsibleContent) with improved styling, replacing the previous Material UI-based implementation.

Styling and structure improvements:

• Refactored layout and spacing to use Tailwind CSS utility classes (e.g., flex, gap-2, justify-center) instead of Material UI's sx prop.
• Enhanced the help instructions for importing .ics files with clearer formatting and a more readable ordered list.

Before	After