Add processing fee option to PDF export modal

- Add checkbox to include 5% processing fee in PDF exports
- Install PDF generation dependencies (@pdfme/common, @pdfme/generator, sharp)
- Add server-side expenses API endpoints
- Update PDF options interface to support processing fee toggle

server/utils/minio.ts

@@ -130,6 +130,11 @@ export const uploadFile = async (filePath: string, fileBuffer: Buffer, contentTy
   });
 };
 
+// Upload buffer (alias for uploadFile for compatibility)
+export const uploadBuffer = async (buffer: Buffer, filePath: string, contentType: string) => {
+  return uploadFile(filePath, buffer, contentType);
+};
+
 // Generate presigned URL for download
 export const getDownloadUrl = async (fileName: string, expiry: number = 60 * 60) => {
   const client = getMinioClient();