feat(admin): aggregate dashboard comparison metrics

tests/test_admin_read.py

@@ -1,12 +1,15 @@
 """Admin M2 读接口测试:大盘聚合 + 用户/流水/提现/反馈列表 + 鉴权拦截。"""
 from __future__ import annotations
 
+from datetime import datetime
+
 import pytest
 from fastapi.testclient import TestClient
 
 from app.admin.main import admin_app
 from app.admin.repositories import admin_user as admin_repo
 from app.db.session import SessionLocal
+from app.models.comparison import ComparisonRecord
 from app.models.feedback import Feedback
 from app.models.wallet import CashTransaction, WithdrawOrder
 from app.repositories import user as user_repo
@@ -69,6 +72,49 @@ def test_dashboard_overview(admin_client: TestClient, admin_token: str) -> None:
     assert "jd_order_count" in data["cps"]
 
 
+def test_dashboard_period_comparison_is_aggregated_by_backend(
+    admin_client: TestClient, admin_token: str
+) -> None:
+    created_at = datetime(2037, 1, 15, 12)
+    rows = [
+        ("dashboard-aggregate-success", "success", 101, 0.1),
+        ("dashboard-aggregate-failed", "failed", 200, 0.2),
+        ("dashboard-aggregate-cancelled", "cancelled", 300, 0.3),
+        ("dashboard-aggregate-running", "running", 400, 0.4),
+    ]
+    db = SessionLocal()
+    try:
+        for trace_id, status, total_ms, llm_cost_yuan in rows:
+            db.add(
+                ComparisonRecord(
+                    trace_id=trace_id,
+                    status=status,
+                    total_ms=total_ms,
+                    llm_cost_yuan=llm_cost_yuan,
+                    created_at=created_at,
+                )
+            )
+        db.commit()
+    finally:
+        db.close()
+
+    response = admin_client.get(
+        "/admin/api/stats/overview",
+        params={"date_from": "2037-01-15", "date_to": "2037-01-15"},
+        headers=_auth(admin_token),
+    )
+    assert response.status_code == 200, response.text
+    comparison = response.json()["period"]["comparison"]
+    assert comparison["total"] == 4
+    assert comparison["completed"] == 2
+    assert comparison["cancelled"] == 1
+    assert comparison["success"] == 1
+    assert comparison["success_rate"] == 0.3333
+    assert comparison["median_duration_ms"] == 151
+    assert comparison["p95_duration_ms"] == 195
+    assert comparison["token_cost_total_yuan"] == pytest.approx(1.0)
+
+
 def test_user_list_and_detail(admin_client: TestClient, admin_token: str) -> None:
     uid = _seed_user_with_data("13800000002")
     r = admin_client.get("/admin/api/users", headers=_auth(admin_token))