Added sort dropdown to printer file manager with options for:

- Name (A-Z / Z-A)
- Size (smallest / largest first)
- Date (oldest / newest first)

Directories are always sorted first regardless of sort option.

frontend/src/api/client.ts

@@ -1470,6 +1470,7 @@ export const api = {
         is_directory: boolean;
         size: number;
         path: string;
+        mtime?: string;
       }>;
     }>(`/printers/${printerId}/files?path=${encodeURIComponent(path)}`),
   getPrinterFileDownloadUrl: (printerId: number, path: string) =>