fix: CUDA 12 needs no extra, only CUDA 13 needs [cu13] for cutlass-dsl

- setup_test_env.sh: only add [cu13] extra for CUDA 13, plain install for CUDA 12
- Update skill docs to match NVIDIA's official installation guide

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: limin2021

scripts/setup_test_env.sh

@@ -26,19 +26,19 @@ fi
 
 # Override nvidia-cutlass-dsl if specified
 if [ -n "${CUTLASS_DSL_VERSION:-}" ]; then
-  # Detect CUDA major version to select the correct extra (cu12 or cu13)
+  # Detect CUDA major version: only CUDA 13+ needs [cu13] extra
   CUDA_MAJOR=$(python -c "import torch; print(torch.version.cuda.split('.')[0])" 2>/dev/null || echo "12")
   if [ "$CUDA_MAJOR" = "13" ]; then
-    CUTLASS_DSL_EXTRA="cu13"
+    CUTLASS_DSL_PKG="nvidia-cutlass-dsl[cu13]==${CUTLASS_DSL_VERSION}"
   else
-    CUTLASS_DSL_EXTRA="cu12"
+    CUTLASS_DSL_PKG="nvidia-cutlass-dsl==${CUTLASS_DSL_VERSION}"
   fi
   echo "========================================"
-  echo "Overriding nvidia-cutlass-dsl with version: ${CUTLASS_DSL_VERSION} [${CUTLASS_DSL_EXTRA}]"
+  echo "Overriding nvidia-cutlass-dsl with: ${CUTLASS_DSL_PKG}"
   echo "========================================"
   # Clean uninstall old packages first (recommended by NVIDIA docs)
   pip uninstall nvidia-cutlass-dsl nvidia-cutlass-dsl-libs-base nvidia-cutlass-dsl-libs-cu12 nvidia-cutlass-dsl-libs-cu13 -y 2>/dev/null || true
-  pip install "nvidia-cutlass-dsl[${CUTLASS_DSL_EXTRA}]==${CUTLASS_DSL_VERSION}"
+  pip install "${CUTLASS_DSL_PKG}"
   echo "nvidia-cutlass-dsl override complete."
   echo ""
 fi