Client side for REST scan planning

### Is your feature request related to a problem or challenge?

Iceberg REST protocol supports remote planning https://github.com/apache/iceberg/blob/main/open-api/rest-catalog-open-api.yaml#L605, it'd be great for Rust to offer a client side implementation

This would to the work ongoing in the reference implementation

https://github.com/apache/iceberg/pull/13004
https://github.com/apache/iceberg/pull/13400

### Describe the solution you'd like

_No response_

### Willingness to contribute

I can contribute to this feature independently

Start by reading the REST scan-planning definition in open-api/rest-catalog-open-api.yaml and the reference implementation work in Apache Iceberg pull requests 13004 and 13400. Map the Rust client scope against that protocol; done means a client-side implementation of the supported remote planning flow, with validation of its behavior.

Written by the indexing model from the issue text.