feat: 操作日志系统 + 日期修复 + 协同去重 + 主题持久化 + 计划自动完成

本次累积提交包含以下功能：

1. 修复：el-date-picker 缺失 value-format 导致日期保存偏移（8处）
2. 新增：协同拜访 visit_group_id 去重机制（完整副本 + 周报合并 + 亮灯去重）
3. 新增：计划自动完成（创建计划检测已有拜访 / 编辑拜访触发）
4. 新增：拜访表单选择客户后自动预填过期计划内容
5. 新增：移动端主题切换按钮 + 后端持久化
6. 新增：操作日志系统 (audit_logs)，全覆盖 8 个模块 CRUD
7. 新增：PC端「我的数据」支局长/领导视角客户经理列

Co-Authored-By: Claude <noreply@anthropic.com>

backend/app/services/leaves.py

@@ -5,6 +5,7 @@ from sqlalchemy.ext.asyncio import AsyncSession
 from app.models.leave import Leave
 from app.models.user import User
 from app.utils.timezone import today_cst
+from app.utils.audit import log_audit
 from app.services.dashboard import get_week_range
 
 
@@ -88,6 +89,7 @@ async def create_leave(
     data: dict,
     submitted_by: UUID,
     role: str,
+    operator_name: str = "",
 ) -> Leave:
     """Create leave. Manager can only create for self; director can create for anyone."""
     if role == "manager":
@@ -108,6 +110,9 @@ async def create_leave(
     db.add(leave)
     await db.commit()
     await db.refresh(leave)
+    # Audit log
+    await log_audit(db, "leave", leave.id, f"{leave.leave_type} ({leave.start_date}~{leave.end_date})", "create", str(submitted_by), operator_name)
+    await db.commit()
     return leave
 
 
@@ -117,6 +122,7 @@ async def update_leave(
     data: dict,
     user_id: UUID,
     role: str,
+    operator_name: str = "",
 ) -> Leave:
     """Update leave. Director can edit any; manager can edit own submitted leaves."""
     leave = await get_leave_by_id(db, leave_id)
@@ -136,6 +142,9 @@ async def update_leave(
 
     await db.commit()
     await db.refresh(leave)
+    # Audit log
+    await log_audit(db, "leave", leave.id, f"{leave.leave_type} ({leave.start_date}~{leave.end_date})", "update", str(user_id), operator_name)
+    await db.commit()
     return leave
 
 
@@ -144,6 +153,7 @@ async def delete_leave(
     leave_id: UUID,
     user_id: UUID,
     role: str,
+    operator_name: str = "",
 ) -> bool:
     """Delete leave. Director can delete any; manager can delete own submitted leaves."""
     leave = await get_leave_by_id(db, leave_id)
@@ -154,8 +164,12 @@ async def delete_leave(
         if str(leave.submitted_by) != str(user_id):
             raise PermissionError("客户经理只能删除自己提交的请假")
 
+    entity_name = f"{leave.leave_type} ({leave.start_date}~{leave.end_date})"
     await db.delete(leave)
     await db.commit()
+    # Audit log
+    await log_audit(db, "leave", leave_id, entity_name, "delete", str(user_id), operator_name)
+    await db.commit()
     return True