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/TargetGroup.test.tsx

@@ -0,0 +1,76 @@
+import "../../../tests/web/test-utils";
+import { render } from "@testing-library/react";
+import { describe, expect, test, vi } from "bun:test";
+
+import type { TargetStatus } from "../../../src/shared/api";
+
+import { TargetGroup } from "../../../src/web/components/TargetGroup";
+
+describe("TargetGroup", () => {
+  const columns = [
+    { colKey: "name", title: "名称" },
+    { colKey: "target", title: "目标" },
+  ];
+
+  const targets: TargetStatus[] = [
+    {
+      currentStreak: null,
+      group: "default",
+      id: 1,
+      interval: "30s",
+      latestCheck: {
+        durationMs: 100,
+        failure: null,
+        matched: true,
+        statusDetail: "200 OK",
+        timestamp: "2025-01-15T10:00:00.000Z",
+      },
+      name: "target-1",
+      recentSamples: [],
+      stats: { availability: 100, downChecks: 0, totalChecks: 10, upChecks: 10 },
+      target: "https://example.com",
+      type: "http",
+    },
+    {
+      currentStreak: null,
+      group: "default",
+      id: 2,
+      interval: "30s",
+      latestCheck: {
+        durationMs: 100,
+        failure: { kind: "error", message: "Failed", path: "$", phase: "status" },
+        matched: false,
+        statusDetail: "500 Internal Server Error",
+        timestamp: "2025-01-15T10:00:00.000Z",
+      },
+      name: "target-2",
+      recentSamples: [],
+      stats: { availability: 50, downChecks: 1, totalChecks: 2, upChecks: 1 },
+      target: "https://example.org",
+      type: "http",
+    },
+  ];
+
+  const onTargetClick = vi.fn();
+
+  test("default 分组不崩溃", () => {
+    const { container } = render(
+      <TargetGroup columns={columns} name="default" onTargetClick={onTargetClick} targets={targets} />,
+    );
+    expect(container.firstChild).not.toBeNull();
+  });
+
+  test("非 default 分组不崩溃", () => {
+    const { container } = render(
+      <TargetGroup columns={columns} name="production" onTargetClick={onTargetClick} targets={targets} />,
+    );
+    expect(container.firstChild).not.toBeNull();
+  });
+
+  test("空 targets 不崩溃", () => {
+    const { container } = render(
+      <TargetGroup columns={columns} name="default" onTargetClick={onTargetClick} targets={[]} />,
+    );
+    expect(container.firstChild).not.toBeNull();
+  });
+});