[CPU] Fix lscpu NUMA node regex to handle quoted - and null in containers

[Monokaix]

Purpose

Fix CPU worker startup crash in Docker containers where NUMA topology is unavailable (e.g., ARM64 on macOS Docker Desktop).

lscpu -J -e=CPU,CORE,NODE outputs "node": "-" (quoted dash) in these environments, but the existing regex only handled "node": - (unquoted dash). This caused all CPUs to be filtered out in get_allowed_cpu_core_node_list(), resulting in:
AssertionError: Not enough allowed NUMA nodes to bind threads of 1 local CPUWorkers. Allowed NUMA nodes are [].

Test Plan

# Reproduce the crash (before fix):
docker run \
    -p 8000:8000 \
    vllm/vllm-openai-cpu:latest-arm64
# Verify lscpu output inside container:
docker run -it --entrypoint /bin/bash vllm/vllm-openai-cpu:latest-arm64
lscpu -J -e=CPU,CORE,NODE
# Confirms "node": "-" (quoted dash)
# Build new image with this fix and re-run the command to make sure it's fixed, and server should start normally
docker run \
    -p 8000:8000 \
    vllm/vllm-openai-cpu:latest-arm64

Test Result

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[gemini-code-assist]

Code Review

This pull request updates the regular expression used to sanitize the JSON output of the lscpu command in vllm/platforms/cpu.py. The modification improves robustness by correctly identifying and replacing various representations of missing NUMA node values, such as "-", -, or null, with a default value of 0 before the string is parsed. I have no feedback to provide as there were no review comments.