Fix production web API routing

frontend/src/api/client.js

@@ -5,8 +5,9 @@ import {
   getAccessToken,
   setAccessToken,
 } from '../utils/session';
+import { resolveApiUrl } from '../config/api';
 
-const API_URL = import.meta.env.VITE_API_URL || 'http://localhost:4000';
+const API_URL = resolveApiUrl();
 
 const client = axios.create({
   baseURL: API_URL,

frontend/src/api/public.js

@@ -1,6 +1,7 @@
 import axios from 'axios';
+import { resolveApiUrl } from '../config/api';
 
-const API_URL = import.meta.env.VITE_API_URL || 'http://localhost:4000';
+const API_URL = resolveApiUrl();
 
 export const verifySignature = (code) => axios.get(`${API_URL}/signatures/verify/${code}`);
 export const getLegalTemplates = () => axios.get(`${API_URL}/legal/templates`);

frontend/src/config/api.js

@@ -0,0 +1,17 @@
+const normalize = (value) => String(value || '').replace(/\/$/, '');
+
+export const resolveApiUrl = () => {
+  if (typeof window !== 'undefined' && window.location?.hostname === 'sign.linkedcorp.net') {
+    return '/api';
+  }
+
+  return normalize(import.meta.env.VITE_API_URL || 'http://192.168.222.40:4000');
+};
+
+export const resolveAndroidApkUrl = () => {
+  if (typeof window !== 'undefined' && window.location?.hostname === 'sign.linkedcorp.net') {
+    return '/api/downloads/android-apk';
+  }
+
+  return `${resolveApiUrl()}/downloads/android-apk`;
+};

frontend/src/pages/auth/LoginPage.jsx

@@ -4,6 +4,7 @@ import { useAuth } from '../../contexts/AuthContext';
 import { Download, PenTool } from 'lucide-react';
 import toast from 'react-hot-toast';
 import { SESSION_EXPIRED_MESSAGE, translateApiError } from '../../utils/session';
+import { resolveAndroidApkUrl } from '../../config/api';
 import packageInfo from '../../../package.json';
 
 export default function LoginPage() {
@@ -12,8 +13,7 @@ export default function LoginPage() {
   const [searchParams, setSearchParams] = useSearchParams();
   const [form, setForm] = useState({ email: '', password: '' });
   const [loading, setLoading] = useState(false);
-  const apiBaseUrl = (import.meta.env.VITE_API_URL || 'http://localhost:4000').replace(/\/$/, '');
-  const androidApkUrl = `${apiBaseUrl}/downloads/android-apk`;
+  const androidApkUrl = resolveAndroidApkUrl();
   const showAndroidDownload = useMemo(() => {
     if (typeof navigator === 'undefined') return false;
     return /Android/i.test(navigator.userAgent || '');