feat(transfer): add per-task operation timeout

docs/content/docs/data-transfer.cn.mdx

@@ -83,9 +83,12 @@ description: 在不同连接、数据库、Schema 或数据库引擎之间批量
 | Upsert | 目标路径支持且能确定键时，按键更新或插入 |
 | 表名大小写 | 保持原样、转小写或转大写；转换后的目标名必须互不冲突 |
 | 批大小 | 控制分页读取和分批写入，默认 1000，可在界面中调整 |
+| 操作超时 | 默认分别继承源连接和目标连接的查询超时；也可为当前传输设置 `0`–`3600` 秒，`0` 表示不限制 |
 
 如果关闭“创建目标表”，目标表必须已经存在且字段可兼容。即使开启建表，跨引擎 DDL 也可能因目标数据库不支持某些类型、默认值、约束或对象而需要人工调整。
 
+操作超时不限制整个传输任务的总时长。支持增量结果流的驱动会把它作为“无进展等待时间”，每次收到数据都会重新计时；只能一次性返回结果的驱动则按单次数据库操作的总耗时计算。自定义值只作用于当前传输及其保存任务，不会修改连接或查询编辑器的超时设置。
+
 <Callout type="warn">**重建结构和数据**会替换现有目标表及其索引、触发器、约束、注释和对象权限为源结构。原表会先被重命名为备份表，传输成功后删除。任一步骤失败则保留备份表，可手工恢复。</Callout>
 
 ## 结构 SQL 预览

docs/content/docs/data-transfer.mdx

@@ -83,9 +83,12 @@ This entry point lists target drivers with implemented transactional writes. It
 | Upsert | Updates or inserts by key when the target path supports it and a usable key is available |
 | Target table name case | Preserve, lowercase, or uppercase; transformed target names must remain unique |
 | Batch size | Controls paged reads and batched writes; the UI default is 1000 |
+| Operation timeout | Inherits the source and target connection query timeouts by default; override this transfer with `0`–`3600` seconds, where `0` means unlimited |
 
 If table creation is disabled, compatible target tables must already exist. Even with table creation enabled, cross-engine DDL may require manual changes when the target does not support a source type, default, constraint, or object.
 
+The operation timeout does not cap the overall transfer duration. Drivers with incremental result streams treat it as an inactivity window that resets whenever data arrives; drivers that return a result all at once apply it to the total duration of each database operation. A custom value affects only this transfer and its saved task, not the connection or query-editor timeout settings.
+
 <Callout type="warn">**Rebuild structure and data** replaces existing target tables and their indexes, triggers, constraints, comments, and object permissions with source structure. The original table is renamed to a backup first, then dropped after a successful transfer. If any step fails, the backup table is retained and can be manually restored.</Callout>
 
 ## Structure SQL Preview