fix: build webf_unit_test target for Windows

The Windows build only built the webf target but not webf_unit_test,
causing the unit test step to fail with exe not found.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: andycall

scripts/tasks.js

@@ -724,6 +724,9 @@ task('build-window-webf-lib', (done) => {
     });
 
   const webfTargets = ['webf'];
+  if (targetJSEngine === 'quickjs') {
+    webfTargets.push('webf_unit_test');
+  }
 
   // build
   execSync(`cmake --build ${bridgeCmakeDir} --target ${webfTargets.join(' ')} --verbose --config ${buildType}`, {