Add unit test and e2e test placeholders to build workflow

Author: Hudson Xing

.github/workflows/build.yml

@@ -32,6 +32,12 @@ jobs:
         run: |
           TARGET_FILE="patched-vscode/src/vs/server/node/webClientServer.ts"
           REQUIRED_TEXT="connect-src 'self' ws: wss: https://main.vscode-cdn.net http://localhost:* https://localhost:* https://login.microsoftonline.com/ https://update.code.visualstudio.com https://*.vscode-unpkg.net/ https://default.exp-tas.com/vscode/ab https://vscode-sync.trafficmanager.net https://vscode-sync-insiders.trafficmanager.net https://*.gallerycdn.vsassets.io https://marketplace.visualstudio.com https://*.blob.core.windows.net https://az764295.vo.msecnd.net  https://code.visualstudio.com https://*.gallery.vsassets.io https://*.rel.tunnels.api.visualstudio.com wss://*.rel.tunnels.api.visualstudio.com https://*.servicebus.windows.net/ https://vscode.blob.core.windows.net https://vscode.search.windows.net https://vsmarketplacebadges.dev https://vscode.download.prss.microsoft.com https://download.visualstudio.microsoft.com https://*.vscode-unpkg.net https://open-vsx.org;"
+
+          if [ ! -f "$TARGET_FILE" ]; then
+            echo "❌ FAIL: Target file $TARGET_FILE does not exist."
+            exit 1
+          fi
+
           if grep -F "$REQUIRED_TEXT" "$TARGET_FILE" > /dev/null; then
             echo "✅ PASS: Required CSP text exists."
           else