[moe] add customized option to moe-a2a-backend (#21786)

python/sglang/srt/layers/moe/utils.py

@@ -26,6 +26,7 @@ class MoeA2ABackend(Enum):
     MORI = "mori"
     ASCEND_FUSEEP = "ascend_fuseep"
     FLASHINFER = "flashinfer"
+    CUSTOMIZED = "customized"
 
     @classmethod
     def _missing_(cls, value):
@@ -57,6 +58,9 @@ class MoeA2ABackend(Enum):
     def is_mori(self):
         return self == MoeA2ABackend.MORI
 
+    def is_customized(self):
+        return self == MoeA2ABackend.CUSTOMIZED
+
 
 class MoeRunnerBackend(Enum):