fix(ci): remove CUDA stubs from LD_LIBRARY_PATH for GPU test runtime

The CI builder image prepends /usr/local/cuda/lib64/stubs to
LD_LIBRARY_PATH (for GPU-less compilation). On H100 with nvidia
RuntimeClass, the stub libcuda.so shadows the real driver library,
causing CUDA_ERROR_STUB_LIBRARY at test runtime. Strip stubs dir
before running tests.

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

.gitlab-ci.yml

@@ -85,7 +85,9 @@ test:
   stage: test
   needs: [check]
   script:
-    # All tests run on H100 node — real CUDA available, no stubs needed
+    # Remove CUDA stubs from LD_LIBRARY_PATH — nvidia RuntimeClass provides real libcuda.so
+    - export LD_LIBRARY_PATH=$(echo "$LD_LIBRARY_PATH" | tr ':' '\n' | grep -v stubs | tr '\n' ':' | sed 's/:$//')
+    - nvidia-smi  # verify GPU access
     - cargo test --workspace --lib -- --skip model_loader::tests
 
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