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/SummaryCards.test.tsx

@@ -0,0 +1,33 @@
+import "../../../tests/web/test-utils";
+import { render } from "@testing-library/react";
+import { describe, expect, test } from "bun:test";
+
+import type { DashboardResponse } from "../../../src/shared/api";
+
+import { SummaryCards } from "../../../src/web/components/SummaryCards";
+
+describe("SummaryCards", () => {
+  const summary: DashboardResponse["summary"] = {
+    down: 2,
+    incidents: 1,
+    lastCheckTime: "2025-01-15T10:00:00.000Z",
+    total: 10,
+    up: 8,
+    window: {
+      from: "2025-01-14T10:00:00.000Z",
+      label: "24h",
+      to: "2025-01-15T10:00:00.000Z",
+    },
+  };
+
+  test("summary 为 null 时不渲染", () => {
+    const { container } = render(<SummaryCards summary={null} />);
+
+    expect(container.firstChild).toBeNull();
+  });
+
+  test("有数据不崩溃", () => {
+    const { container } = render(<SummaryCards summary={summary} />);
+    expect(container.firstChild).not.toBeNull();
+  });
+});