260324:2133 Refactor correspondence & rfa

frontend/lib/api/files.ts

@@ -0,0 +1,26 @@
+import apiClient from '@/lib/api/client';
+
+export interface UploadedAttachment {
+  id: number;
+  uuid: string;
+  tempId: string;
+  originalFilename: string;
+  mimeType: string;
+  fileSize: number;
+  isTemporary: boolean;
+}
+
+export const filesApi = {
+  upload: async (file: File): Promise<UploadedAttachment> => {
+    const formData = new FormData();
+    formData.append('file', file);
+    const response = await apiClient.post('/files/upload', formData, {
+      headers: { 'Content-Type': 'multipart/form-data' },
+    });
+    return response.data;
+  },
+
+  uploadMany: async (files: File[]): Promise<UploadedAttachment[]> => {
+    return Promise.all(files.map((f) => filesApi.upload(f)));
+  },
+};