fix: KPI详情'历史数据'Tab空白 — get_kpi附带kpi_values历史数据

根因: GET /kpis/{kpi_id} 只返回KPI定义信息, 未附带历史值
前端期望 kv.values(图表+表格数据) → 拿到undefined → Tab空白

修复: get_kpi 查询该KPI的kpi_values(按期间升序), 附带
values[{period, actual_value, source_type, data_status, source_batch}]

验证: F_REVENUE 10条(2026-01~08+), 渠补率9条

backend/app/api/kpis.py

@@ -482,7 +482,25 @@ def get_kpi(kpi_id: int, db: Session = Depends(get_db), entity_id: int = Depends
     # 账套隔离: 禁止跨企业读取 (2026-08-23 P1a)
     if kpi.entity_id != entity_id:
         raise HTTPException(404, "KPI不存在")
-    return kpi_to_dict(kpi)
+    result = kpi_to_dict(kpi)
+    # 附带历史数据（前端KPI详情"历史数据"Tab依赖）
+    # 2026-08-26修复: 原实现只返回定义信息，values缺失导致历史数据Tab空白
+    vals = db.query(KPIValue).filter(
+        KPIValue.kpi_id == kpi_id,
+        KPIValue.actual_value.isnot(None),
+    ).order_by(KPIValue.period.asc()).all()
+    result["values"] = [
+        {
+            "id": v.id,
+            "period": v.period,
+            "actual_value": v.actual_value,
+            "source_type": v.source_type,
+            "data_status": v.data_status,
+            "source_batch": v.source_batch,
+        }
+        for v in vals
+    ]
+    return result
 
 
 def _validate_kpi_data(data: dict, db: Session, current_kpi_id: Optional[int] = None, is_update: bool = False):