feat: support E2B sandbox timeout updates

[zhongwen666]

closes #1348

Summary

Support the E2B Python SDK's sandbox.set_timeout() using ROCK's existing auto-clear timeout model.

Key changes

• Add the timeout endpoint with strict non-negative int32 validation, empty 204 responses, and E2B-formatted 404 errors.
• Round seconds up to whole minutes and disable renewal for E2B control-plane status checks while preserving normal ROCK sliding timeouts.
• Extend existing E2B SDK integration/live tests and update the English and Chinese compatibility guides.