[Core] Add Qwen-MoE dense/source-layout and routing-side hooks #48

Part of #47.

Goal

Add Qwen-MoE support for the safe hook subset that can reuse the current transport and DB path.

This issue is scoped to:

• Dense/source-layout hooks.
• Token-major MoE routing-side hooks:
  • router_logits
  • topk_ids
  • topk_weights
• vLLM Qwen2-MoE integration and validation.
• HF hook surface wiring where practical.

Full dynamic expert-local EP artifacts are intentionally out of scope for this issue and should be tracked separately.

Completed

• Added Qwen2-MoE vLLM hook variants.
• Added MoE routing-side hooks:
  • router_logits
  • topk_ids
  • topk_weights
• Kept supported hooks in token-major/source-layout form so they reuse the existing transport and DB path.
• Added vLLM EP test controls:
  • E2E_ENABLE_EP
  • E2E_ALL2ALL_BACKEND
• Validated vLLM paths on the current machine:
  • TP=2, EP disabled, compare passed.
  • TP=2, EP enabled with allgather_reducescatter, eager passed.
  • TP=2, EP enabled with allgather_reducescatter, CUDA graph passed.

Tasks

• Add Qwen2-MoE vLLM hook variants.
• Add MoE routing-side hook specs.
• Add vLLM EP test controls.
• Validate vLLM TP=2 EP-disabled path.
• Validate vLLM TP=2 EP-enabled allgather_reducescatter eager path.
• Validate vLLM TP=2 EP-enabled allgather_reducescatter CUDA graph path.
• Document remaining full EP artifact work as follow-up scope.