refactor: 前端架构重构 — hook拆分、组件拆分、类型筛选器动态化、Meta API

- 后端新增 GET /api/meta 端点（checkerRegistry.supportedTypes）及 MetaResponse 类型
- 前端 hook 拆分为 use-queries.ts（全局查询+useMeta）和 use-target-detail.ts（Drawer状态）
- TargetDetailDrawer 拆分为 OverviewTab + HistoryTab + history-table-columns + stats.ts
- 类型筛选器由 meta API 动态驱动，删除 target-type-display 静态映射
- 列定义改为工厂函数 createTargetTableColumns(checkerTypes)，TargetGroup 新增 columns prop
- 修复 StatusDonut key、StatusBar maxSlots prop、TrendChart 移除 loading prop
- 补充 utils/time、utils/stats、动态列工厂测试，删除旧 mapping 测试
- 同步 delta specs 到主 specs，归档 frontend-architecture-refactor change

tests/web/utils/stats.test.ts

@@ -0,0 +1,29 @@
+import { describe, expect, test } from "bun:test";
+
+import type { TrendPoint } from "../../../src/shared/api";
+
+import { computeTrendStats } from "../../../src/web/utils/stats";
+
+describe("computeTrendStats", () => {
+  test("空趋势返回 0 统计", () => {
+    expect(computeTrendStats([])).toEqual({ downChecks: 0, totalChecks: 0, upChecks: 0 });
+  });
+
+  test("汇总总检查、正常和异常数量", () => {
+    const points: TrendPoint[] = [
+      { availability: 80, avgDurationMs: 100, hour: "2025-01-01T00:00:00.000Z", totalChecks: 10 },
+      { availability: 40, avgDurationMs: 200, hour: "2025-01-01T01:00:00.000Z", totalChecks: 5 },
+    ];
+
+    expect(computeTrendStats(points)).toEqual({ downChecks: 5, totalChecks: 15, upChecks: 10 });
+  });
+
+  test("按每个趋势点四舍五入正常数量", () => {
+    const points: TrendPoint[] = [
+      { availability: 33.3, avgDurationMs: null, hour: "2025-01-01T00:00:00.000Z", totalChecks: 3 },
+      { availability: 66.7, avgDurationMs: null, hour: "2025-01-01T01:00:00.000Z", totalChecks: 3 },
+    ];
+
+    expect(computeTrendStats(points)).toEqual({ downChecks: 3, totalChecks: 6, upChecks: 3 });
+  });
+});

tests/web/utils/time.test.ts

@@ -0,0 +1,29 @@
+import { describe, expect, test } from "bun:test";
+
+import { subtractHours } from "../../../src/web/utils/time";
+
+describe("subtractHours", () => {
+  test("正常扣减小时", () => {
+    const result = subtractHours(new Date("2025-01-15T12:00:00.000Z"), 3);
+
+    expect(result.toISOString()).toBe("2025-01-15T09:00:00.000Z");
+  });
+
+  test("跨天扣减", () => {
+    const result = subtractHours(new Date("2025-01-15T02:00:00.000Z"), 6);
+
+    expect(result.toISOString()).toBe("2025-01-14T20:00:00.000Z");
+  });
+
+  test("跨月扣减", () => {
+    const result = subtractHours(new Date("2025-03-01T01:00:00.000Z"), 2);
+
+    expect(result.toISOString()).toBe("2025-02-28T23:00:00.000Z");
+  });
+
+  test("扣减 0 小时返回相同时间", () => {
+    const result = subtractHours(new Date("2025-01-15T12:00:00.000Z"), 0);
+
+    expect(result.toISOString()).toBe("2025-01-15T12:00:00.000Z");
+  });
+});