Async API for RestCatalog

### Feature Request / Improvement

RestCatalog currently uses synchronous HTTP calls, while most catalog operations are network io-bound. Native async support would help async consumers and high-concurrency use cases in general.

We could introduce a separate AsyncRestCatalog, preserving the existing synchronous API.

asyncio.to_thread()/running in a dedicated executor is a possible workaround but doesn't give the same benefits as native support as we'd still have the limitations of the sync client (one worker thread per in-flight request being the most annoying in this case).

We can start small without necessarily the full ops coverage, wdyt?

Comienza por la implementación existente de RestCatalog y determina qué operaciones del catálogo utilizan actualmente llamadas HTTP síncronas. Define el alcance inicial de AsyncRestCatalog preservando la API síncrona; el issue deja abiertos la cobertura exacta de las operaciones y el enfoque de validación.

Escrito por el modelo de indexación a partir del texto del issue.