web(vercel): serve static assets before SPA fallback (filesystem handle); fixes manifest.json returning index.html

Author: aimuhire

mobile/vercel.json

@@ -1,7 +1,10 @@
 {
   "version": 2,
   "outputDirectory": "build/web",
-  "routes": [{ "src": "/(.*)", "dest": "/index.html" }],
+  "routes": [
+    { "handle": "filesystem" },
+    { "src": "/(.*)", "dest": "/index.html" }
+  ],
   "buildCommand": "npm run build",
   "installCommand": "npm install",
   "framework": null