yurekami 3c8358c328 [v1][CP] Improve DCP/PCP/MTP error messages with actionable guidance
Replace cryptic AssertionErrors with informative RuntimeErrors that:
- Explain what DCP (Decode Context Parallel) and PCP (Prefill Context
  Parallel) are
- List compatible attention backends
- Provide environment variable instructions (VLLM_ATTENTION_BACKEND)
- Include documentation links

Fixes #28407

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Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
Signed-off-by: yurekami <249254018+yurekami@users.noreply.github.com>
2025-12-18 20:05:16 +09:00
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