- None.

`ArrayData` validation used unchecked `usize` arithmetic when combining
array lengths and offsets. In optimized builds, very large lengths could
wrap these calculations and allow invalid `ArrayData` metadata to pass
validation.

This adds checked arithmetic for length plus offset calculations in
`ArrayData` validation, including offset-buffer validation and related
typed-buffer sizing paths.

Yes. This adds regression coverage for overflowing offset-buffer and
typed-buffer length calculations.

Validated with:

```bash
cargo test -p arrow-data overflow --release
```

Invalid `ArrayData` whose length and offset cannot be represented
without overflow now returns an validation error consistently across
build modes. There are no API changes.