[kexinoh]

Adds optional llm_sign response signatures for OpenAI-compatible Chat Completions and Responses API responses. Disabled by default via VLLM_LLM_SIGN_ENABLED. Includes env vars, signing hooks, docs, and focused tests. Local validation: py_compile passed; llm_sign runtime tests passed (13 passed); pip check passed.

[github-actions]

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[mergify]

Documentation preview: https://vllm--43558.org.readthedocs.build/en/43558/

[gemini-code-assist]

Code Review

This pull request introduces experimental support for llm_sign response signatures in OpenAI-compatible Chat Completions and Responses API endpoints. The implementation includes a new llm_sign.py module for handling cryptographic signing, updates to the serving logic to attach signatures when enabled via environment variables, and comprehensive unit tests. Documentation has also been added to guide users on installation and configuration. I have no feedback to provide as there were no review comments to evaluate.