docs: describe NotifyUser as off by default with the settings lab opt-in

Author: RealKai42

docs/en/reference/tools.md

@@ -108,7 +108,7 @@ In the TUI, updates appear in the `Updates` panel above the input box, with one
 
 In the desktop app and the web UI (`kimi web`), each update appears in the conversation as a progress row showing its title; click it to read the message.
 
-The feature is on by default. To turn it off, set `KIMI_CODE_EXPERIMENTAL_NOTIFY_USER=0`, put `[experimental] notify_user = false` in `config.toml`, or switch it off in `/experiments`; this applies to sessions created afterwards. Sessions created while it is disabled have neither the tool nor its prompt guidance.
+The feature is off by default. To enable it, set `KIMI_CODE_EXPERIMENTAL_NOTIFY_USER=1`, put `[experimental] notify_user = true` in `config.toml`, or turn it on in `/experiments` (in the TUI) or in the settings' Lab section (in the desktop app and web UI); this applies to sessions created afterwards. Sessions created while it is disabled have neither the tool nor its prompt guidance.
 
 Existing sessions keep their notification tool availability and prompt unchanged, including after reopening. Turning the feature off hides the panel and disables its shortcuts; any existing `NotifyUser` calls finish normally and report that the update was not displayed. Turning it back on restores display for sessions that already have the tool. If a session was created with the feature disabled, start a new session to use updates. Changing only this flag in `/experiments` does not reload the session.
 

docs/zh/reference/tools.md

@@ -108,7 +108,7 @@ Plan 模式是一种受约束的工作状态：进入后 `Write` 与 `Edit` 只
 
 在桌面端和 Web UI（`kimi web`）中，每条更新以进展行的形式出现在对话里，显示其标题，点击可展开阅读正文。
 
-该功能默认开启。如需关闭，可设置 `KIMI_CODE_EXPERIMENTAL_NOTIFY_USER=0`、在 `config.toml` 中写入 `[experimental] notify_user = false`，或在 `/experiments` 中关闭；对之后新建的会话生效。关闭状态下创建的会话不会提供该工具，也不会包含相关提示词指导。
+该功能默认关闭。如需开启，可设置 `KIMI_CODE_EXPERIMENTAL_NOTIFY_USER=1`、在 `config.toml` 中写入 `[experimental] notify_user = true`，或在 TUI 的 `/experiments` 或桌面端和 Web UI 设置的实验室中打开；仅对之后新建的会话生效。关闭状态下创建的会话不会提供该工具，也不会包含相关提示词指导。
 
 已有会话的通知工具可用性和提示词保持不变，重新打开会话后也一样。关闭功能会隐藏面板并停用其快捷键；已有的 `NotifyUser` 调用仍正常结束，并返回更新未展示的说明。重新开启后，已具有该工具的会话恢复展示；如果会话是在关闭状态下创建的，需要新建会话才能使用进展更新。在 `/experiments` 中仅修改这个开关不会重载会话。