feat: LDAP 账号管理 — OU管理/添加用户/删除用户/批量导入

后端新增 4 个 LDAP 管理端点:
- POST /ldap-config/create-ou: 创建组织单元
- POST /ldap-config/create-user: 创建单个用户 (SSHA加密)
- POST /ldap-config/delete-user: 删除用户
- POST /ldap-config/batch-import-ldap: 批量导入用户
- POST /ldap-config/user-list: 查询用户列表(恢复)

前端 LdapConfigPage 增强:
- LDAP 账号管理折叠区(配置存在即显示)
- OU 下拉选择 + 根节点选项 + 数量统计
- 用户列表表格(全选/单选/DN显示)
- 新建 OU 弹框(名称+父级DN+描述)
- 添加用户弹框(用户名+密码+显示名+邮箱+目标OU)
- 删除选中用户按钮(确认后批量删除)

前端 UsersPage BatchImportModal 三 Tab:
- 本地导入 / 导入到 LDAP / 从 LDAP 导入

测试修复:
- test_user_endpoint.py: 分页格式兼容
- test_users.py: 分页格式兼容
- test_system_settings.py: 精简后配置项匹配

backend/app/services/ticket_scheduler.py

@@ -112,7 +112,8 @@ async def _run_async_execution(ticket_id: int) -> None:
 
 
 async def _execute_scheduled_ticket(ticket_id: int) -> None:
-    """执行定时工单 — 创建独立数据库会话执行。"""
+    """执行定时工单 — 状态切换后 create_task 后台执行，不阻塞 APScheduler。"""
+    import asyncio
     from app.core.database import async_session
     from app.models.ticket import Ticket as TicketModel
     from app.models.instance import Instance
@@ -121,56 +122,56 @@ async def _execute_scheduled_ticket(ticket_id: int) -> None:
     from sqlalchemy import select
     import json
 
-    logger.info("开始执行定时工单 %d", ticket_id)
+    logger.info("定时工单 %d 触发执行", ticket_id)
 
+    # 先切状态为 executing
     async with async_session() as db:
-        try:
-            result = await db.execute(select(TicketModel).where(TicketModel.id == ticket_id))
-            ticket = result.scalar_one_or_none()
-            if not ticket:
-                logger.error("定时工单 %d 不存在", ticket_id)
-                return
+        result = await db.execute(select(TicketModel).where(TicketModel.id == ticket_id))
+        ticket = result.scalar_one_or_none()
+        if not ticket:
+            logger.error("定时工单 %d 不存在", ticket_id)
+            return
+        if ticket.status != "scheduled":
+            logger.warning("工单 %d 状态已变更 (%s)，跳过", ticket_id, ticket.status)
+            return
+        ticket.status = "executing"
+        await db.commit()
 
-            if ticket.status != "scheduled":
-                logger.warning("工单 %d 状态已变更 (%s)，跳过执行", ticket_id, ticket.status)
-                return
-
-            ticket.status = "executing"
-            await db.commit()
-            await db.refresh(ticket)
-
-            inst_result = await db.execute(select(Instance).where(Instance.id == ticket.instance_id))
-            instance = inst_result.scalar_one_or_none()
-            if not instance:
-                ticket.status = "failed"
-                ticket.execute_result = json.dumps({"status": "failed", "errors": ["数据源实例不存在"]}, ensure_ascii=False)
-                ticket.execute_time = datetime.now(timezone.utc)
-                await db.commit()
-                return
-
-            instance.password = decrypt_password(instance.password)
-            executor = TicketExecutor()
-            report = await executor.execute(ticket, instance)
-
-            ticket.status = "success" if report.status == "success" else "failed"
-            ticket.execute_result = report.to_json()
-            ticket.execute_time = datetime.now(timezone.utc)
-            await db.commit()
-
-            logger.info("定时工单 %d 执行完成: %s", ticket_id, report.status)
-
-        except Exception as e:
-            logger.exception("定时工单 %d 执行异常", ticket_id)
+    # 后台 task 执行，APScheduler 立即释放
+    async def _do_exec():
+        async with async_session() as db:
             try:
-                result = await db.execute(select(TicketModel).where(TicketModel.id == ticket_id))
-                ticket = result.scalar_one_or_none()
-                if ticket:
-                    ticket.status = "failed"
-                    ticket.execute_result = json.dumps({"status": "failed", "errors": [f"{type(e).__name__}: {e}"]}, ensure_ascii=False)
-                    ticket.execute_time = datetime.now(timezone.utc)
+                t = (await db.execute(select(TicketModel).where(TicketModel.id == ticket_id))).scalar_one_or_none()
+                if not t or t.status != "executing":
+                    return
+                inst = (await db.execute(select(Instance).where(Instance.id == t.instance_id))).scalar_one_or_none()
+                if not inst:
+                    t.status = "failed"
+                    t.execute_result = json.dumps({"status": "failed", "errors": ["数据源实例不存在"]}, ensure_ascii=False)
+                    t.execute_time = datetime.now(timezone.utc)
                     await db.commit()
-            except Exception:
-                logger.exception("更新定时工单 %d 失败状态也失败", ticket_id)
+                    return
+                inst.password = decrypt_password(inst.password)
+                executor = TicketExecutor()
+                report = await executor.execute(t, inst)
+                t.status = "success" if report.status == "success" else "failed"
+                t.execute_result = report.to_json()
+                t.execute_time = datetime.now(timezone.utc)
+                await db.commit()
+                logger.info("定时工单 %d 执行完成: %s", ticket_id, report.status)
+            except Exception as e:
+                logger.exception("定时工单 %d 执行异常", ticket_id)
+                try:
+                    t = (await db.execute(select(TicketModel).where(TicketModel.id == ticket_id))).scalar_one_or_none()
+                    if t:
+                        t.status = "failed"
+                        t.execute_result = json.dumps({"status": "failed", "errors": [f"{type(e).__name__}: {e}"]}, ensure_ascii=False)
+                        t.execute_time = datetime.now(timezone.utc)
+                        await db.commit()
+                except Exception:
+                    logger.exception("更新定时工单 %d 失败状态也失败", ticket_id)
+
+    asyncio.get_event_loop().create_task(_do_exec())
 
 
 def cancel_ticket_execution(ticket_id: int) -> bool: