修复刷新缓存与样式测试隔离

src/main/java/com/example/workutils/system/ui/MainWindow.java

@@ -54,6 +54,7 @@ public class MainWindow {
     }
 
     public void refreshNavItems(List<NavItem> newItems) {
+        embeddedCache.clear();
         navItems = new ArrayList<>(newItems);
         navigationRail.setItems(navItems);
         showWelcomePage();
@@ -155,7 +156,10 @@ public class MainWindow {
         if (item.action != null) {
             item.action.run();
         }
-        showEmbeddedFor(item);
+        if (!showEmbeddedFor(item)) {
+            navigationRail.clearSelection();
+            showWelcomePage();
+        }
     }
 
     private void showPluginToolbar(String title) {
@@ -200,15 +204,17 @@ public class MainWindow {
         currentEmbedded = null;
     }
 
-    private void showEmbeddedFor(NavItem item) {
+    private boolean showEmbeddedFor(NavItem item) {
         if (item.pluginId == null) {
             hidePluginToolbar();
-            return;
+            return false;
         }
         EmbeddedEntry entry = embeddedCache.get(item.pluginId);
         if (entry != null) {
             switchToEmbedded(item.pluginId, entry);
+            return true;
         }
+        return false;
     }
 
     public void embedPlugin(String pluginId, String ignoredIcon, String name, Parent content) {