[Refactor] Rename cudagraph_support to aclgraph_support (#3104)

### What this PR does / why we need it?
Updates the `cudagraph_support` attribute to `aclgraph_support` to use
terminology appropriate for the Ascend platform (ACL graphs instead of
CUDA graphs).

This change also explicitly disables graph support for the MLA attention
backend.

### Does this PR introduce _any_ user-facing change?
None.

### How was this patch tested?
None needed.

- vLLM version: v0.10.2
- vLLM main:
5aeb925452

Signed-off-by: Yizhou Liu <liu_yizhou@outlook.com>

vllm_ascend/attention/attention_v1.py

@@ -199,8 +199,8 @@ class AscendMetadata:
 
 
 class AscendAttentionMetadataBuilder:
-    # Does this backend/builder support CUDA Graphs for attention (default: no).
-    cudagraph_support: ClassVar[AttentionCGSupport] = \
+    # Does this backend/builder support ACL Graphs for attention (default: no).
+    aclgraph_support: ClassVar[AttentionCGSupport] = \
         AttentionCGSupport.UNIFORM_SINGLE_TOKEN_DECODE
     # Does this backend/builder reorder the batch?
     # If not, set this to None. Otherwise set it to the query

vllm_ascend/attention/mla_v1.py

@@ -1,5 +1,6 @@
 from dataclasses import dataclass
-from typing import TYPE_CHECKING, NamedTuple, Optional, Tuple, Type, TypeVar
+from typing import (TYPE_CHECKING, ClassVar, NamedTuple, Optional, Tuple, Type,
+                    TypeVar)
 
 import torch
 import torch_npu
@@ -12,6 +13,7 @@ from vllm.distributed import get_tensor_model_parallel_world_size, get_tp_group
 from vllm.model_executor.layers.linear import (LinearBase,
                                                UnquantizedLinearMethod)
 from vllm.utils import cdiv, round_down
+from vllm.v1.attention.backends.utils import AttentionCGSupport
 
 from vllm_ascend.ascend_config import get_ascend_config
 from vllm_ascend.attention.attention_v1 import AscendAttentionState
@@ -163,6 +165,9 @@ M = TypeVar("M", bound=AscendMLAMetadata)
 
 
 class AscendMLAMetadataBuilder:
+    # Does this backend/builder support ACL Graphs for attention (default: no).
+    aclgraph_support: ClassVar[AttentionCGSupport] = \
+        AttentionCGSupport.NEVER
     """
     NOTE: Please read the comment at the top of the file before trying to
     understand this class

vllm_ascend/worker/model_runner_v1.py

@@ -3259,8 +3259,8 @@ class NPUModelRunner(LoRAModelRunnerMixin):
                 builder = attn_group.metadata_builder
             else:
                 builder = attn_group.get_metadata_builder()
-            if builder.cudagraph_support.value < min_ag_support.value:
-                min_ag_support = builder.cudagraph_support
+            if builder.aclgraph_support.value < min_ag_support.value:
+                min_ag_support = builder.aclgraph_support
                 min_ag_builder_name = builder.__class__.__name__
 
         # This is an imitation of compilation_config.splitting_ops_contain_attention()