[Feature] Add close_session functionality to Sandbox SDK

[bird2426]

Feature Category

• Sandbox
• Actions
• Deployments
• SDK & API
• Envhub
• CLI
• Performance & Optimization
• Documentation & Examples

Problem Statement
Currently, the Sandbox SDK allows creating sessions (create_session) and running commands (run_in_session), but it lacks a direct method to close a specific session. Users cannot programmatically terminate a session once it's no longer needed, which is essential for resource management and session lifecycle control.

Proposed Solution
Add a close_session method to the Sandbox class in the SDK. This method should wrap the underlying CloseSessionRequest and call the sandbox runtime to terminate the specified session.

Detailed Feature Description