Document vLLM-Omni as a production serving option for VoxCPM2
alongside the existing Nano-vLLM reference. Mirrors the addition in
README_zh.md, and adds an ecosystem table entry.
Install snippet follows the upstream vLLM-Omni installation guide
(from source, since vllm-omni is rapidly evolving).
Signed-off-by: Yueqian Lin <linyueqian@outlook.com>
Yueqian Lin