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.

next.config.js

@@ -7,6 +7,7 @@ import "./src/env.js";
 /** @type {import("next").NextConfig} */
 const config = {
   output: "standalone",
+  reactCompiler: true,
   serverExternalPackages: ["pg"],
 };