fix(时长): 所有时长计算排除非工作日 + 修复两处时区多算8小时

- get_wip_tasks/get_people_workload/get_people_history/product active_duration_hours/analytics 均改用 working_duration_hours
- 修复 get_wip_tasks 与 active_duration_hours 的 naive 时间误标北京时间 bug(DB实存UTC，原多算8小时)
- 每处读取 holidays 表排除配置的放假日期

backend/app/services/analytics_service.py

@@ -114,11 +114,12 @@ def _to_bj(dt: datetime | None) -> datetime | None:
     return dt
 
 
-def _duration_hours(start: datetime | None, end: datetime) -> float:
-    """计算单台耗时（小时），无开始时间返回 0。"""
+def _duration_hours(start: datetime | None, end: datetime, holidays: set = None) -> float:
+    """计算单台耗时（工作小时，排除周末/节假日），无开始时间返回 0。"""
     if not start:
         return 0.0
-    return (end - start).total_seconds() / 3600
+    from app.core.time_utils import working_duration_hours
+    return working_duration_hours(start, end, holidays)
 
 
 # ============================================================
@@ -142,10 +143,15 @@ async def get_capability_profile(
         Task, TASK_STATUS_WIP, TASK_STATUS_PENDING, TASK_STATUS_COMPLETED,
     )
     from app.models.product import Product
+    from app.models.holiday import Holiday
     from app.core.time_utils import get_beijing_time
 
     now = get_beijing_time()
 
+    # 读取节假日（排除非工作日）
+    hres = await db.execute(select(Holiday.day))
+    holidays = {r[0] for r in hres}
+
     stmt = (
         select(
             Task.assignee_id, Task.status,
@@ -196,7 +202,7 @@ async def get_capability_profile(
             "hours": 0.0, "prio": 9,
             "first_start": None, "last_completed": None,
         })
-        entry["hours"] += _duration_hours(start, end)
+        entry["hours"] += _duration_hours(start, end, holidays)
         if start and (entry["first_start"] is None or start < entry["first_start"]):
             entry["first_start"] = start
         completed_dt = _to_bj(row[4]) if row[4] else None