fix: Fix undefined junit-vintage-engine version and update DuckDuckGo selector

- Replace ${junit-vintage-engine.version} with ${junit.version} to fix
  build failure from undefined property
- Update DuckDuckGo search field selector from #searchbox_input to
  [data-ssg-id='ai-searchbox-input']

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: wakaleo

pom.xml

@@ -87,7 +87,7 @@
         <dependency>
             <groupId>org.junit.vintage</groupId>
             <artifactId>junit-vintage-engine</artifactId>
-            <version>${junit-vintage-engine.version}</version>
+            <version>${junit.version}</version>
             <scope>test</scope>
         </dependency>
         <dependency>

src/test/java/starter/search/SearchForm.java

@@ -3,6 +3,6 @@
 import net.serenitybdd.screenplay.targets.Target;
 
 class SearchForm {
-    static Target SEARCH_FIELD = Target.the("search field").locatedBy("#searchbox_input");
+    static Target SEARCH_FIELD = Target.the("search field").locatedBy("[data-ssg-id='ai-searchbox-input']");
 
 }