http_backoff

This release enhances the `hf-cli` skill by enabling automatic installation and synchronization, introduces flexible engine flag management for Inference Endpoints, and adds Baseten as a new inference provider. It also includes several quality-of-life improvements and bug fixes.

This release introduces Sandboxes, isolated cloud machines accessible via API and CLI, and significantly speeds up snapshot downloads by caching repository tree listings. The underlying CLI framework was also migrated from Typer to Click.