fix: 看板4项体验修复 — 时间/身份证/日期筛选/通知跳转

1. 完整16位产品身份证号显示（不再截断）
2. 日期筛选栏: 今天 | 近7天 | 近30天 | 全部
   - 后端 recent-activity 支持 since/until ISO参数
   - 默认展示今天动态，可按时间范围切换
3. 操作人兜底: TaskLog无operator_id时用任务assignee_id
4. 未读通知可点击跳转通知页面 + 快捷入口增加通知中心

backend/app/services/dashboard_service.py

@@ -1,4 +1,5 @@
 """Dashboard 统计服务"""
+from datetime import datetime
 from sqlalchemy import select, func
 from sqlalchemy.ext.asyncio import AsyncSession
 from pydantic import BaseModel
@@ -69,31 +70,43 @@ async def get_dashboard_stats(db: AsyncSession) -> DashboardStats:
     )
 
 
-async def get_recent_activity(db: AsyncSession, limit: int = 10) -> list[RecentActivity]:
+async def get_recent_activity(
+    db: AsyncSession, limit: int = 10,
+    since: datetime | None = None, until: datetime | None = None,
+) -> list[RecentActivity]:
     from app.models.task_log import TaskLog
     from app.models.task import Task
     from app.models.product import Product
     from app.core.time_utils import BEIJING_TZ
 
     stmt = (
-        select(TaskLog, Task.task_name, Product.serial_number)
+        select(TaskLog, Task.task_name, Product.serial_number, Task.assignee_id)
         .join(Task, TaskLog.task_id == Task.id)
         .join(Product, Task.product_id == Product.id)
-        .order_by(TaskLog.created_at.desc())
-        .limit(limit)
     )
+    if since:
+        stmt = stmt.where(TaskLog.created_at >= since)
+    if until:
+        stmt = stmt.where(TaskLog.created_at <= until)
+    stmt = stmt.order_by(TaskLog.created_at.desc()).limit(limit)
     result = await db.execute(stmt)
     rows = result.all()
 
-    # 收集 operator_id → 批量翻译中文姓名
-    operator_ids = list({row[0].operator_id for row in rows if row[0].operator_id})
+    # 收集 operator_id + 兜底 assignee_id → 批量翻译中文姓名
+    raw_ids: set[str] = set()
+    for row in rows:
+        op = row[0].operator_id
+        if op:
+            raw_ids.add(op)
+        elif row[3]:  # assignee_id 兜底
+            raw_ids.add(row[3])
     name_map: dict[str, str] = {}
-    if operator_ids:
+    if raw_ids:
         from app.services.mom_cache import get_display_names
-        name_map = get_display_names(operator_ids)
+        name_map = get_display_names(list(raw_ids))
 
     activities: list[RecentActivity] = []
-    for log, task_name, product_sn in rows:
+    for log, task_name, product_sn, task_assignee in rows:
         action_label = _action_label(log.action_type)
         # 强制转北京时间显示
         t = log.created_at
@@ -105,9 +118,9 @@ async def get_recent_activity(db: AsyncSession, limit: int = 10) -> list[RecentA
             time_str = t.strftime("%m-%d %H:%M")
         else:
             time_str = ""
-        # operator_id: 优先显示中文姓名 → 英文用户名兜底 → 无记录时为空
-        op = log.operator_id
-        op_display = name_map.get(op, op or "")
+        # operator_id: 优先显示中文姓名 → 英文用户名兜底 → 任务负责人兜底 → 空
+        op = log.operator_id or task_assignee or ""
+        op_display = name_map.get(op, op)
         activities.append(RecentActivity(
             action=action_label,
             task_name=task_name or "",