[Doc] Add Disaggregation Prefill for dpsk-v32 doc

[Potabk]

What this PR does / why we need it?

Add Disaggregation Prefill for dpsk-v32 doc

Does this PR introduce any user-facing change?

How was this patch tested?

• vLLM version: v0.11.0rc3
• vLLM main: vllm-project/vllm@releases/v0.11.0

[github-actions]

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[gemini-code-assist]

Code Review

This pull request adds a new documentation page for setting up prefill-decode disaggregation with the DeepSeek v3.2 model. The new tutorial provides step-by-step instructions for environment verification, rank table generation, and service deployment. I've identified a critical syntax error in the prefiller deployment script and a likely configuration omission in the decoder deployment script that would prevent users from successfully following the tutorial. The suggested changes correct these issues.

[gemini-code-assist]

The vllm serve command is missing a line continuation character \ at the end of this line. This will cause a shell syntax error and prevent the command from running correctly.

Suggested change

	--additional-config '{"torchair_graph_config":{"enabled":true,"graph_batch_sizes":[16]}}'
	--additional-config '{"torchair_graph_config":{"enabled":true,"graph_batch_sizes":[16]}}' \

[gemini-code-assist]

The decoder node configuration is missing the --additional-config to enable torchair graph mode, which is enabled on the prefiller node. For consistency and to ensure correct distributed operation, the decoder should also have graph mode enabled.

Suggested change

	--gpu-memory-utilization 0.9 \
	--gpu-memory-utilization 0.9 \
	--additional-config '{"torchair_graph_config":{"enabled":true,"graph_batch_sizes":[16]}}' \