Redact sensitive environment variable values in vllm_process logs

[coderabbitai]

Context

In auto_tune_vllm/execution/vllm_process.py (lines 51-61), the get_os_env_vars method currently logs raw environment variable values which can potentially leak secrets or PII.

Recommendation

Update the logging to redact sensitive values or log only the keys of environment variables rather than their actual values.

Related

• PR: refactor: pull out providers and vllm into separate modules #104
• Comment: refactor: pull out providers and vllm into separate modules #104 (comment)
• Requested by: @ephoris