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/lib/navigation.ts

@@ -6,6 +6,7 @@ import {
   Building,
   Receipt,
   BarChart2,
+  Shield,
 } from "lucide-react";
 
 export interface NavLink {
@@ -35,6 +36,11 @@ export const navigationConfig: NavSection[] = [
     title: "Account",
     links: [
       { name: "Settings", href: "/dashboard/settings", icon: Settings },
+      {
+        name: "Administration",
+        href: "/dashboard/administration",
+        icon: Shield,
+      },
     ],
   },
 ];