### What this PR does / why we need it?
Provide sample guidance for running long-sequence DeepSeek across
multiple nodes
To guide users on using the context parallel feature, a practical
example is provided.
### Does this PR introduce _any_ user-facing change?
### How was this patch tested?
- vLLM version: release/v0.13.0
- vLLM main:
bc0a5a0c08
Signed-off-by: weiguihua2 <weiguihua2@huawei.com>