- Add `react-router-dom` for client-side routing.
- Add `shadcn` components: `Sidebar`, `Dialog`, `Button`, `ScrollArea`, `Avatar`, `Badge`, `Card`, `Sheet`, `Tooltip`, `Separator`, `Input`, `Label`.
- Implement `AppSidebar` with navigation to Characters and Equipments.
- Implement `Characters` page displaying character avatars.
- Implement `Equipments` page with:
- Horizontal scrollable category filter (multi-select).
- Equipment grid layout.
- "Extract Equipment" button opening a `Dialog` (refactored from `Extractor` component but maintaining original UI design).
- Update `Equipment` API and Service to support filtering by multiple categories.
- Add database index to `Equipment` table on `[category, subCategory]`.
- Refactor `App.tsx` and `Layout.tsx` to use the new routing and sidebar structure.
- Remove legacy `Stash` and `Extractor` components.