fix: address Node 20 requirement and vercel.json config

1. setup-ts-sdk.sh: require Node.js 20+ (needed for global File constructor)
2. vercel.json: replace unsupported top-level deploy object with per-app config
   reference, each demo keeps its own vercel.json

Author: Nitin-kumar-yadav1307

examples/quickstart-scripts/setup-ts-sdk.sh

@@ -37,8 +37,8 @@ if ! command -v node &> /dev/null; then
 fi
 
 NODE_VERSION=$(node -v | cut -d'v' -f2 | cut -d'.' -f1)
-if [ "$NODE_VERSION" -lt 18 ]; then
-    echo -e "${RED}❌ Node.js 18+ is required. Current version: $(node -v)${NC}"
+if [ "$NODE_VERSION" -lt 20 ]; then
+    echo -e "${RED}❌ Node.js 20+ is required. Current version: $(node -v)${NC}"
     exit 1
 fi
 

examples/vercel.json

@@ -1,22 +1,5 @@
 {
-  "deploy": {
-    "react-sdk-demo": {
-      "name": "urbackend-react-demo",
-      "buildCommand": "cd examples/react-sdk-demo && npm install && npm run build",
-      "outputDirectory": "examples/react-sdk-demo/dist",
-      "installCommand": "cd examples/react-sdk-demo && npm install"
-    },
-    "sdk-kanban": {
-      "name": "urbackend-kanban",
-      "buildCommand": "cd examples/sdk-kanban/client && npm install && npm run build",
-      "outputDirectory": "examples/sdk-kanban/client/dist",
-      "installCommand": "cd examples/sdk-kanban/client && npm install"
-    },
-    "social-demo": {
-      "name": "urbackend-social-demo",
-      "buildCommand": "cd examples/social-demo/client && npm install && npm run build",
-      "outputDirectory": "examples/social-demo/client/dist",
-      "installCommand": "cd examples/social-demo/client && npm install"
-    }
-  }
-}
+  "$schema": "https://openapi.vercel.sh/doc.json",
+  "comment": "Per-application Vercel configuration has been moved to each demo's own vercel.json. This root file is kept for documentation. See: examples/react-sdk-demo/vercel.json, examples/sdk-kanban/vercel.json, examples/social-demo/vercel.json"
+}
+</write_to_file></tool_call>