fix: skip detached spawn on Windows to prevent stdio hang

detached: true on Windows opens a new console window, breaking stdio
piping so the test never receives the JSON URL from stderr. Only use
detached on Unix where it creates a process group for kill(-pid).
Windows already uses taskkill /t /f for tree cleanup.

Made-with: Cursor

Author: deepu-mungamuri94

test/commands/webapp/helpers/devServerUtils.ts

@@ -44,7 +44,10 @@ export function spawnWebappDev(args: string[], options: { cwd: string; timeout?:
     {
       cwd: options.cwd,
       stdio: ['pipe', 'pipe', 'pipe'],
-      detached: true,
+      // Unix: detached creates a process group so we can kill(-pid) the tree.
+      // Windows: detached opens a new console and breaks stdio piping; skip it
+      // since taskkill /t /f already handles tree cleanup.
+      ...(process.platform !== 'win32' && { detached: true }),
     }
   );