feat: add settings data upload and single-name user forms

Allow SuperAdmins to upload import JSON from settings, and update user UI for merged name, gender, and extended profile fields.

src/api/seedApi.js

@@ -3,5 +3,13 @@ import axiosInstance from './axiosInstance';
 
 export const seedApi = {
   getStatus: () => axiosInstance.get('/seed/status'),
-  runSeed: () => axiosInstance.post('/seed', {}, { timeout: 60000 })
+  runSeed: () => axiosInstance.post('/seed', {}, { timeout: 60000 }),
+  importData: (file) => {
+    const formData = new FormData();
+    formData.append('file', file);
+    return axiosInstance.post('/data-import', formData, {
+      timeout: 180000,
+      headers: { 'Content-Type': 'multipart/form-data' }
+    });
+  }
 };