Update Navbar and DownloadPage to hide download link in Electron app

- Add Electron detection to DownloadPage
- Show friendly message when accessed from desktop app
- Hide Download link in Navbar when running in Electron
- Add vercel.json configuration for deployment
- Update build script for Vercel compatibility

Author: pankaj-bind

frontend/package.json

@@ -40,7 +40,7 @@
      "scripts": {
           "start": "react-scripts start",
           "build": "react-scripts build",
-          "vercel-build": "CI=false react-scripts build",
+          "vercel-build": "react-scripts build",
           "test": "react-scripts test",
           "eject": "react-scripts eject",
           "electron": "electron .",

frontend/vercel.json

@@ -0,0 +1,21 @@
+{
+  "framework": "create-react-app",
+  "buildCommand": "npm run build",
+  "outputDirectory": "build",
+  "installCommand": "npm install",
+  "devCommand": "npm start",
+  "env": {
+    "CI": "false"
+  },
+  "build": {
+    "env": {
+      "CI": "false"
+    }
+  },
+  "rewrites": [
+    {
+      "source": "/(.*)",
+      "destination": "/index.html"
+    }
+  ]
+}