fix: Configure Vercel rewrites for SPA routing to fix direct /privacy access

Author: aimuhire

mobile/vercel.json

@@ -3,11 +3,11 @@
   "buildCommand": "",
   "installCommand": "",
   "outputDirectory": "build/web",
-  "builds": [
-    { "src": "build/web/**", "use": "@vercel/static" }
-  ],
-  "routes": [
-    { "src": "/(.*)", "dest": "/build/web/$1" }
+  "rewrites": [
+    {
+      "source": "/(.*)",
+      "destination": "/index.html"
+    }
   ]
 }