feat: 动态粒度趋势图，支持 auto bucket 选择 + P95 延迟 + 状态条

tests/server/app.test.ts

@@ -319,10 +319,12 @@ describe("API 路由", () => {
     expect(body.trend[0]).toMatchObject({
       availability: 50,
       avgDurationMs: 150,
+      bucketEnd: "2025-01-01T01:00:00.000Z",
       bucketStart: "2025-01-01T00:00:00.000Z",
       downChecks: 2,
       maxDurationMs: 200,
       minDurationMs: 100,
+      p95DurationMs: 200,
       totalChecks: 4,
       upChecks: 2,
     });
@@ -350,7 +352,11 @@ describe("API 路由", () => {
       totalChecks: 0,
       upChecks: 0,
     });
-    expect(body.trend).toEqual([]);
+    expect(body.trend.length).toBeGreaterThan(0);
+    body.trend.forEach((point: { availability: number; totalChecks: number }) => {
+      expect(point.totalChecks).toBe(0);
+      expect(point.availability).toBe(0);
+    });
   });
 
   test("查询不存在的目标返回 404", async () => {
@@ -394,7 +400,7 @@ describe("API 路由", () => {
   test("metrics 无效 bucket 和不存在目标返回错误", async () => {
     const targets = store.getTargets();
     const invalidBucket = await fetch(
-      `${baseUrl}/api/targets/${targets[0]!.id}/metrics?from=2025-01-01T00:00:00.000Z&to=2025-01-01T01:00:00.000Z&bucket=5m`,
+      `${baseUrl}/api/targets/${targets[0]!.id}/metrics?from=2025-01-01T00:00:00.000Z&to=2025-01-01T01:00:00.000Z&bucket=invalid`,
     );
     const missingTarget = await fetch(
       `${baseUrl}/api/targets/99999/metrics?from=2025-01-01T00:00:00.000Z&to=2025-01-01T01:00:00.000Z`,