[Tiny] Fix Import Error for Pure TP config with flashinfer_mxfp4 (#30426)

Co-authored-by: Claude Opus 4.8 <noreply@anthropic.com>

python/sglang/srt/layers/moe/moe_runner/runner.py

@@ -65,6 +65,11 @@ class MoeRunner:
             self.runner_core = None  # FlashInfer CUTLASS only supports fused path
         elif runner_backend.is_flashinfer_mxfp4():
             self.runner_core = None  # FlashInfer MXFP4 only supports fused path
+            # Import flashinfer_cutlass here (not at module top, to avoid a circular
+            # import) to register the flashinfer_mxfp4 fused func before the pool lookup.
+            from sglang.srt.layers.moe.moe_runner import (  # noqa: F401
+                flashinfer_cutlass,
+            )
         elif runner_backend.is_cutlass():
             self.runner_core = None  # CUTLASS uses the direct cutlass_moe_fp4 path
         else: