[Refactor] Replace the implementations of o_proj, q_b_proj, and kv_b_proj with custom_op for sharded CP (#5698)

### What this PR does / why we need it?
Based on the Sharded-CP feature
PR:https://github.com/vllm-project/vllm-ascend/pull/4702;
RFC:https://github.com/vllm-project/vllm/issues/30055

This PR officially integrates Deepseek V3.2's DSA-CP support on the
basis of https://github.com/vllm-project/vllm-ascend/pull/4702,
improving inference efficiency and scalability under mixed
prefill-decode workloads. The main improvements include:
- Replace the implementations of o_proj, q_b_proj, and kv_b_proj with
custom_op for TP=1.

### Does this PR introduce _any_ user-facing change?

### How was this patch tested?

- vLLM version: v0.13.0
- vLLM main:
2f4e6548ef

---------

Signed-off-by: zzhx1 <zzh_201018@outlook.com>
Signed-off-by: chenxiao <Jaychou1620@Gmail.com>
Signed-off-by: Kurumi5210 <jaychou1620@gmail.com>
Co-authored-by: clrs97 <524936896@qq.com>
Co-authored-by: chenxiao <Jaychou1620@Gmail.com>

vllm_ascend/utils.py

@@ -1119,11 +1119,6 @@ def dispose_layer(layer: Any):
             dispose_tensor(attr_value)
 
 
-def replace_layer(original_layer: Any, new_layer: Any):
-    original_layer.__class__ = new_layer.__class__
-    original_layer.__dict__ = new_layer.__dict__
-
-
 def check_kv_extra_config(vllm_config):
 
     def _check(name: str, config: dict):
@@ -1166,17 +1161,31 @@ def singleton(cls):
     return get_instance
 
 
-@lru_cache(maxsize=1)
-def get_current_model_config():
-    from vllm.config import get_current_vllm_config
-    vllm_config = get_current_vllm_config()
-    return vllm_config.model_config
-
-
 #TODO: Temporarily use enable_sp to enable the dsa_cp feature of ds32. and subsequent updates will introduce new interfaces. --zzhx1
 @lru_cache(maxsize=1)
 def enable_dsa_cp() -> bool:
     from vllm.config import get_current_vllm_config
+
     vllm_config = get_current_vllm_config()
-    is_ds_v32 = hasattr(vllm_config.model_config.hf_config, "index_topk")
-    return is_ds_v32 and enable_sp()
+    if vllm_config is None:
+        return False
+
+    model_config = getattr(vllm_config, "model_config", None)
+    if model_config is None:
+        return False
+
+    hf_text_config = getattr(model_config, "hf_text_config", None)
+    if hf_text_config is None:
+        return False
+
+    return hasattr(hf_text_config, "index_topk")
+
+
+@lru_cache(maxsize=1)
+def enable_dsa_cp_with_layer_shard() -> bool:
+    if not enable_dsa_cp():
+        return False
+    from vllm.config import get_current_vllm_config
+    vllm_config = get_current_vllm_config()
+    is_prefill_instance = vllm_config.kv_transfer_config is not None and vllm_config.kv_transfer_config.is_kv_producer
+    return is_prefill_instance