Add Array.toSorted/toReversed/toSpliced transformer

## Feature Request

Add a transformer to convert spread-then-mutate patterns to non-mutating array methods.

### Baseline Status
- **Status:** Newly Available (2023)
- **Feature:** Array.prototype.toSorted(), toReversed(), toSpliced()

### Transformations

```js
// Before
[...arr].sort()
[...arr].reverse()
[...arr].splice(...)

// After
arr.toSorted()
arr.toReversed()
arr.toSpliced(...)
```

### Priority
Medium - These are non-mutating versions, safer and clearer.

### Note
Only available with `--baseline newly-available` flag.

### References
- MDN (toSorted): https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/toSorted
- MDN (toReversed): https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/toReversed
- MDN (toSpliced): https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/toSpliced
- Catalog: See BASELINE_TRANSFORMERS.md #10 (Newly Available)