fix: wire CCCL preload into build+launch chain + pre-submission verification

- patch_ops.sh: call cccl_preload/build_cccl_preload.sh (new CCCL deps)
  instead of old build_cccl_preload_allocator.sh (mock)
- computility-run.yaml: add LD_PRELOAD + CCCL_ALLOC_DISABLE env vars
- Remove old mock files: cccl_preload_allocator.cu, build script, test
- .dockerignore: exclude cccl_upstream/ upstream_ref/ vllm/ *.zip
- verify_submission.sh: 31-point pre-submission check
  (file structure, CCCL chain, path matching, prebuilt integrity,
   corex imports, docker context, GPU smoke test)

computility-run.yaml

@@ -49,3 +49,7 @@ env:
       value: '1'
     - name: PYTORCH_CUDA_ALLOC_CONF
       value: max_split_size_mb:512
+    - name: LD_PRELOAD
+      value: /workspace/qwen3_6_scripts/libcccl_allocator.so
+    - name: CCCL_ALLOC_DISABLE
+      value: '0'