feat: add administration page and account role management

- Implemented `AdministrationContent` component for managing account roles.
- Created `AdministrationPage` to serve as the main entry point for administration tasks.
- Added PDF preview functionality with `PdfPreviewFrame` component for invoice generation.
- Introduced `InputColor` component for advanced color selection with various formats.
- Established color conversion utilities in `color-converter.ts` for handling color formats.
- Defined appearance-related schemas and types in `appearance.ts` for consistent theme management.

src/components/forms/business-form.tsx

@@ -143,6 +143,7 @@ export function BusinessForm({ businessId, mode }: BusinessFormProps) {
   // Load business data when editing
   useEffect(() => {
     if (business && mode === "edit") {
+      // eslint-disable-next-line react-hooks/set-state-in-effect -- Sync loaded business data into the edit form.
       setFormData({
         name: business.name,
         nickname: business.nickname ?? "",