feat: KDocs 上传增强 + 离线监控 + Bug修复

KDocs 上传功能增强:
- 搜索优化：只用姓名搜索 + C列验证，避免匹配到错误单元格
- 有效行范围：支持配置起始行/结束行，限制上传区域
- 图片覆盖：支持覆盖单元格已有图片（Escape + Delete）
- 配置持久化：kdocs_row_start/row_end 保存到数据库（v18迁移）

二次登录功能:
- 登录后立即再次登录，让"上次登录时间"显示为刚刚

KDocs 离线监控:
- 每5分钟检测金山文档登录状态
- 离线时发送邮件通知管理员（每次掉线只通知一次）
- 恢复在线后重置通知状态

Bug 修复:
- 任务日志搜索账号关键词报错500：添加异常处理

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

routes/admin_api/core.py

@@ -680,6 +680,8 @@ def update_system_config_api():
     kdocs_image_column = data.get("kdocs_image_column")
     kdocs_admin_notify_enabled = data.get("kdocs_admin_notify_enabled")
     kdocs_admin_notify_email = data.get("kdocs_admin_notify_email")
+    kdocs_row_start = data.get("kdocs_row_start")
+    kdocs_row_end = data.get("kdocs_row_end")
 
     if max_concurrent is not None:
         if not isinstance(max_concurrent, int) or max_concurrent < 1:
@@ -787,6 +789,22 @@ def update_system_config_api():
             if not is_valid:
                 return jsonify({"error": error_msg}), 400
 
+    if kdocs_row_start is not None:
+        try:
+            kdocs_row_start = int(kdocs_row_start)
+        except (ValueError, TypeError):
+            return jsonify({"error": "起始行必须是数字"}), 400
+        if kdocs_row_start < 0:
+            return jsonify({"error": "起始行不能为负数"}), 400
+
+    if kdocs_row_end is not None:
+        try:
+            kdocs_row_end = int(kdocs_row_end)
+        except (ValueError, TypeError):
+            return jsonify({"error": "结束行必须是数字"}), 400
+        if kdocs_row_end < 0:
+            return jsonify({"error": "结束行不能为负数"}), 400
+
     old_config = database.get_system_config() or {}
 
     if not database.update_system_config(
@@ -810,6 +828,8 @@ def update_system_config_api():
         kdocs_image_column=kdocs_image_column,
         kdocs_admin_notify_enabled=kdocs_admin_notify_enabled,
         kdocs_admin_notify_email=kdocs_admin_notify_email,
+        kdocs_row_start=kdocs_row_start,
+        kdocs_row_end=kdocs_row_end,
     ):
         return jsonify({"error": "更新失败"}), 400
 
@@ -1091,30 +1111,44 @@ def get_running_tasks_api():
 @admin_required
 def get_task_logs_api():
     """获取任务日志列表（支持分页和多种筛选）"""
-    limit = int(request.args.get("limit", 20))
-    offset = int(request.args.get("offset", 0))
+    try:
+        limit = int(request.args.get("limit", 20))
+        limit = max(1, min(limit, 200))  # 限制 1-200 条
+    except (ValueError, TypeError):
+        limit = 20
+
+    try:
+        offset = int(request.args.get("offset", 0))
+        offset = max(0, offset)
+    except (ValueError, TypeError):
+        offset = 0
+
     date_filter = request.args.get("date")
     status_filter = request.args.get("status")
     source_filter = request.args.get("source")
     user_id_filter = request.args.get("user_id")
-    account_filter = request.args.get("account")
+    account_filter = (request.args.get("account") or "").strip()
 
     if user_id_filter:
         try:
             user_id_filter = int(user_id_filter)
-        except ValueError:
+        except (ValueError, TypeError):
             user_id_filter = None
 
-    result = database.get_task_logs(
-        limit=limit,
-        offset=offset,
-        date_filter=date_filter,
-        status_filter=status_filter,
-        source_filter=source_filter,
-        user_id_filter=user_id_filter,
-        account_filter=account_filter,
-    )
-    return jsonify(result)
+    try:
+        result = database.get_task_logs(
+            limit=limit,
+            offset=offset,
+            date_filter=date_filter,
+            status_filter=status_filter,
+            source_filter=source_filter,
+            user_id_filter=user_id_filter,
+            account_filter=account_filter if account_filter else None,
+        )
+        return jsonify(result)
+    except Exception as e:
+        logger.error(f"获取任务日志失败: {e}")
+        return jsonify({"logs": [], "total": 0, "error": "查询失败"})
 
 
 @admin_api_bp.route("/task/logs/clear", methods=["POST"])