Add type definition for Math.sumPrecise (ES2025 / TC39 proposal)

还没有人认领这个 Issue。

---

### Bug report

#### 📝 Description

`Math.sumPrecise` is part of the [TC39 `proposal-math-sum`](https://github.com/tc39/proposal-math-sum) which reached **Stage 4 on 2025-07-28**, making it part of **ES2026** (not ES2025 as originally stated — the proposal missed the ES2025 cutoff by about one month). Major runtimes like **Bun**, **Firefox 137+**, and **Safari 18.4** have already implemented it, though V8/Node.js has not yet.

However, TypeScript does **not** include type definitions for this API — searching through all `lib.es*.d.ts` files yields no results for `sumPrecise`.

#### 🐛 The problem

This causes a compile error:

```
Property 'sumPrecise' does not exist on type 'Math'. ts(2339)
```

Users are forced to either:
- Use workarounds like type augmentation (`global.d.ts`)
- Fall back to `@ts-expect-error`
- Use incorrect alternatives like `Array.reduce((a, b) => a + b)` which lose precision

#### ✅ Expected behavior

The `interface Math` should be extended in `lib.esnext.math.d.ts`:

```typescript
interface Math {
/**
* Returns the sum of the values in the iterable using a more precise
* summation algorithm than naive floating-point addition.
* Returns `-0` if the iterable is empty.
* @param numbers An iterable (such as an Array) of numbers.
* @throws {TypeError} If `numbers` is not iterable, or if any value in the iterable is not of type `number`.
* @throws {RangeError} If the iterable yields 2^53 or more values.
*/
sumPrecise(numbers: Iterable): number;
}
```

#### 🔗 Related
- TC39 Proposal: https://github.com/tc39/proposal-math-sum
- Stage 4 meeting notes: https://github.com/tc39/notes/blob/main/meetings/2025-07/july-28.md#mathsumprecise-for-stage-4
- MDN Docs: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Math/sumPrecise
- Firefox 137+: shipped
- Safari 18.4 (JavaScriptCore): shipped
- Bun: shipped
- V8 / Node.js / Chrome: not yet

---

从 lib.esnext.math.d.ts 开始，将 Math.sumPrecise 所需的声明与链接的 TC39 提案和现有的 Math 定义进行比较。当 Math 接口以文档所述的数字 iterable 签名公开 sumPrecise，并且 TypeScript 无需 augmentation 或错误抑制即可接受调用时，工作就完成了。

由索引模型根据 Issue 内容生成。