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/server/api/routers/invoiceTemplates.ts

@@ -72,7 +72,10 @@ export const invoiceTemplatesRouter = createTRPCRouter({
       });
 
       if (!existing) {
-        throw new TRPCError({ code: "NOT_FOUND", message: "Template not found" });
+        throw new TRPCError({
+          code: "NOT_FOUND",
+          message: "Template not found",
+        });
       }
 
       // If setting as default, unset others of same type
@@ -108,7 +111,10 @@ export const invoiceTemplatesRouter = createTRPCRouter({
       });
 
       if (!existing) {
-        throw new TRPCError({ code: "NOT_FOUND", message: "Template not found" });
+        throw new TRPCError({
+          code: "NOT_FOUND",
+          message: "Template not found",
+        });
       }
 
       await ctx.db