[Good First Issue] Actions 支持自定义每个操作项的 Tooltip

> 🎓 OSS26 轻训营 · 个人认领题（Good First Issue）
> 关联原始 issue：#1834

### 背景
Actions 操作项的 Tooltip 当前固定为 `title={label}`，无法自定义或关闭。

### 模块
`packages/x/components/actions/`（`interface.ts` / `ActionsItem.tsx`）

### 任务
新增 `tooltip?: string | TooltipProps | false`，`false` 时不渲染 Tooltip。

### 验收
- 自定义 / 关闭 Tooltip 的 demo
- 单测
- 中英文档

Start with packages/x/components/actions/interface.ts and ActionsItem.tsx to understand the existing label-based Tooltip behavior. Add the requested customization, demo, unit test, and Chinese and English documentation; done means custom and disabled Tooltips are demonstrated and covered by tests.

Written by the indexing model from the issue text.