fix: Add static file serving for public/ directory on Vercel

vercel.json

@@ -8,6 +8,10 @@
     {
       "src": "api/proxy.js",
       "use": "@vercel/node"
+    },
+    {
+      "src": "public/**",
+      "use": "@vercel/static"
     }
   ],
   "routes": [
@@ -18,6 +22,10 @@
     {
       "src": "/api/(.*)",
       "dest": "/api/index.js"
+    },
+    {
+      "src": "/(.*)",
+      "dest": "/public/$1"
     }
   ],
   "headers": [