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/app/dashboard/administration/page.tsx

@@ -0,0 +1,23 @@
+import { Suspense } from "react";
+import { DataTableSkeleton } from "~/components/data/data-table";
+import { PageHeader } from "~/components/layout/page-header";
+import { HydrateClient } from "~/trpc/server";
+import { AdministrationContent } from "./_components/administration-content";
+
+export default async function AdministrationPage() {
+  return (
+    <div className="page-enter space-y-6">
+      <PageHeader
+        title="Administration"
+        description="Manage account access and platform administration"
+        variant="gradient"
+      />
+
+      <HydrateClient>
+        <Suspense fallback={<DataTableSkeleton columns={1} rows={4} />}>
+          <AdministrationContent />
+        </Suspense>
+      </HydrateClient>
+    </div>
+  );
+}