Build out home dashboard and simplify topbar layout.

Add hero section with stats and quick actions on the home page, remove the unused topbar search bar, and rename the assistants nav item.

Co-authored-by: Cursor <cursoragent@cursor.com>

src/components/layout/Sidebar.tsx

@@ -19,7 +19,7 @@ const navItems: Array<{
   icon: React.ComponentType<{ size?: number }>;
 }> = [
   { key: "home", label: "控制台", icon: Home },
-  { key: "assistants", label: "小助手管理", icon: Bot },
+  { key: "assistants", label: "创建助手", icon: Bot },
   { key: "components", label: "组件库", icon: Boxes },
   { key: "history", label: "历史记录", icon: Clock3 },
   { key: "test", label: "测试助手", icon: PlayCircle },