fix: Add explicit type annotations to createUserFn handler

TanStack Start's inputValidator requires explicit type annotation on handler's
data parameter. This fixes the 'invalid input: expected object, received undefined'
error when creating users.

Author: sonali-hanchinamani

src/server/users.ts

@@ -1,34 +1,32 @@
 /**
  * Server functions for user management.
  *
- * Calls the LibreChat Admin API (/api/admin/users) for list, search, and delete.
- * Create user is not yet wired.
+ * Calls the LibreChat Admin API (/api/admin/users) for list, search, create, and delete.
  */
 
 import { z } from 'zod';
 import { queryOptions } from '@tanstack/react-query';
 import { SystemRoles } from 'librechat-data-provider';
 import { createServerFn } from '@tanstack/react-start';
-import type { AdminUserSearchResult } from '@librechat/data-schemas';
-import type { TUser } from 'librechat-data-provider';
+import type { AdminUserListItem, AdminUserSearchResult } from '@librechat/data-schemas';
 import { apiFetch, extractApiError } from './utils/api';
 
 // ── Server functions ─────────────────────────────────────────────────
 
 export const getUsersFn = createServerFn({ method: 'GET' }).handler(
-  async (): Promise<{ users: TUser[] }> => {
+  async (): Promise<{ users: AdminUserListItem[] }> => {
     const response = await apiFetch('/api/admin/users');
     if (!response.ok) {
       throw new Error(`Failed to fetch users: ${response.status}`);
     }
-    const json = (await response.json()) as { users: TUser[] };
+    const json = (await response.json()) as { users: AdminUserListItem[] };
     return { users: json.users ?? [] };
   },
 );
 
 export const usersQueryOptions = queryOptions({
   queryKey: ['users'],
-  queryFn: () => getUsersFn().then((r) => r.users),
+  queryFn: () => getUsersFn().then((r) => r.users as AdminUserListItem[]),
   staleTime: 30_000,
 });
 
@@ -40,9 +38,23 @@ export const createUserFn = createServerFn({ method: 'POST' })
       role: z.nativeEnum(SystemRoles),
     }),
   )
-  .handler(async (): Promise<{ user: TUser }> => {
-    throw new Error('Not implemented: createUserFn');
-  });
+  .handler(
+    async ({
+      data,
+    }: {
+      data: { name: string; email: string; role: SystemRoles };
+    }): Promise<{ user: AdminUserListItem }> => {
+      const response = await apiFetch('/api/admin/users', {
+        method: 'POST',
+        body: JSON.stringify(data),
+      });
+      if (!response.ok) {
+        await extractApiError(response, 'Failed to create user');
+      }
+      const json = (await response.json()) as { user: AdminUserListItem };
+      return json;
+    },
+  );
 
 export const deleteUserFn = createServerFn({ method: 'POST' })
   .inputValidator(z.object({ id: z.string() }))
@@ -57,7 +69,7 @@ export const deleteUserFn = createServerFn({ method: 'POST' })
 
 export const searchUsersFn = createServerFn({ method: 'GET' })
   .inputValidator(z.object({ query: z.string() }))
-  .handler(async ({ data }): Promise<{ users: AdminUserSearchResult[] }> => {
+  .handler(async ({ data }) => {
     const response = await apiFetch(`/api/admin/users/search?q=${encodeURIComponent(data.query)}`);
     if (!response.ok) {
       await extractApiError(response, 'Failed to search users');