[Feat] support basic pcp&dcp for qwen3next (#6091)

### What this PR does / why we need it?
This PR implements Context Parallelism (CP) support for the Qwen3-Next
model, including PCP (Parallel Context Parallelism) and DCP
(Dynamic/Data Context Parallelism).

- vLLM version: v0.15.0
- vLLM main:
f176443446

---------

Signed-off-by: SunnyLee219 <3294305115@qq.com>
Signed-off-by: Jingchun Gao <gaojingchun1@huawei.com>
Signed-off-by: 白永斌 <baiyongbin3@h-partners.com>
Signed-off-by: Bai Yongbin <845473182@qq.com>
Co-authored-by: SunnyLee219 <3294305115@qq.com>
Co-authored-by: Jingchun Gao <gaojingchun1@huawei.com>
Co-authored-by: 白永斌 <baiyongbin3@h-partners.com>
Co-authored-by: Mengqing Cao <cmq0113@163.com>

vllm_ascend/ops/triton/fla/chunk_delta_h.py

@@ -38,6 +38,7 @@ def chunk_gated_delta_rule_fwd_kernel_h_blockdim64(
     ht,
     cu_seqlens,
     chunk_offsets,
+    h_update,
     T,
     H: tl.constexpr,
     Hg: tl.constexpr,
@@ -72,6 +73,7 @@ def chunk_gated_delta_rule_fwd_kernel_h_blockdim64(
 
     b_h1_bv1 = tl.zeros([128, 64], dtype=tl.float32)
     b_h1_bv2 = tl.zeros([128, 64], dtype=tl.float32)
+    # create b_hupd_bv1 and b_hupd_bv2
 
     v_start1 = 0
     v_start2 = 64
@@ -204,6 +206,7 @@ def chunk_gated_delta_rule_fwd_h(
     assert K <= 256, "current kernel does not support head dimension larger than 256."
 
     h = k.new_empty(B, NT, H, K, V)
+    h_update = k.new_empty(B, NT, H, K, K)
     final_state = k.new_empty(N, H, K, V, dtype=torch.float32) if output_final_state else None
 
     v_new = torch.empty_like(u) if save_new_value else None
@@ -223,6 +226,7 @@ def chunk_gated_delta_rule_fwd_h(
         ht=final_state,
         cu_seqlens=cu_seqlens,
         chunk_offsets=chunk_offsets,
+        h_update=h_update,
         T=T,
         H=H,
         Hg=Hg,