test: 重构测试体系 — 建立组件测试层、补充后端测试、清理低质量测试

- 新增 jsdom + @testing-library/react 组件测试环境
- 新增 12 个组件测试，覆盖所有前端组件
- 补充后端 middleware 和 helpers 单元测试
- 删除伪测试 use-target-detail-logic.test.ts
- 精简过度枚举的 color-threshold.test.ts
- 新增 bunfig.toml 配置测试 preload
- 更新 DEVELOPMENT.md 测试章节
- 安装 @types/jsdom 修复类型声明

tests/web/components/RefreshCountdown.test.tsx

@@ -0,0 +1,64 @@
+import "../../../tests/web/test-utils";
+import { render } from "@testing-library/react";
+import { describe, expect, test, vi } from "bun:test";
+
+import { RefreshCountdown } from "../../../src/web/components/RefreshCountdown";
+
+describe("RefreshCountdown", () => {
+  test("手动模式不崩溃", () => {
+    const { container } = render(
+      <RefreshCountdown
+        dashboardUpdatedAt={0}
+        isFetching={false}
+        isManualRefresh={true}
+        onRefresh={vi.fn()}
+        refreshInterval={30000}
+      />,
+    );
+
+    expect(container.firstChild).not.toBeNull();
+  });
+
+  test("自动模式不崩溃", () => {
+    const now = Date.now();
+    const { container } = render(
+      <RefreshCountdown
+        dashboardUpdatedAt={now - 10000}
+        isFetching={false}
+        isManualRefresh={false}
+        onRefresh={vi.fn()}
+        refreshInterval={30000}
+      />,
+    );
+
+    expect(container.firstChild).not.toBeNull();
+  });
+
+  test("fetching 状态不崩溃", () => {
+    const { container } = render(
+      <RefreshCountdown
+        dashboardUpdatedAt={1000}
+        isFetching={true}
+        isManualRefresh={false}
+        onRefresh={vi.fn()}
+        refreshInterval={30000}
+      />,
+    );
+
+    expect(container.firstChild).not.toBeNull();
+  });
+
+  test("未刷新状态不崩溃", () => {
+    const { container } = render(
+      <RefreshCountdown
+        dashboardUpdatedAt={0}
+        isFetching={false}
+        isManualRefresh={false}
+        onRefresh={vi.fn()}
+        refreshInterval={30000}
+      />,
+    );
+
+    expect(container.firstChild).not.toBeNull();
+  });
+});