test(webview): 添加Tooltip组件的单元测试mock

- 为Tooltip相关组件添加mock实现以简化测试
- Tooltip、TooltipTrigger和TooltipContent均被mock为简单div容器
- 保持SessionList组件测试环境的纯净与稳定
- 改善测试执行的性能和可靠性

Author: hqwlkj

packages/vscode-ide-companion/src/webview/components/SessionList.test.tsx

@@ -63,6 +63,12 @@ vi.mock("@/webview/components/ui/item", () => ({
   ItemActions: vi.fn(({ children }) => <div>{children}</div>),
 }));
 
+vi.mock("@/webview/components/ui/tooltip", () => ({
+  Tooltip: vi.fn(({ children }) => <div>{children}</div>),
+  TooltipTrigger: vi.fn(({ children }) => <div>{children}</div>),
+  TooltipContent: vi.fn(({ children }) => <div>{children}</div>),
+}));
+
 describe("SessionList", () => {
   const today = new Date();
   const yesterday = new Date(today);