test: avoid shell by default in e2e process helper

Co-Authored-By: Codex <noreply@anthropic.com>

web/e2e/utils/process.js

@@ -4,7 +4,7 @@ export function startProcess(command, args, options = {}) {
   const child = spawn(command, args, {
     cwd: options.cwd,
     env: { ...process.env, ...(options.env || {}) },
-    shell: process.platform === 'win32',
+    shell: options.shell ?? false,
     stdio: ['ignore', 'pipe', 'pipe'],
   });