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)

.dockerignore

@@ -1,3 +1,18 @@
 **/__pycache__
 **/*.pyc
 **/.git
+
+# Large directories not needed in Docker image
+cccl_upstream/
+upstream_ref/
+vllm/
+ixformer_sdk/
+muh/
+ex_engine/
+docs/
+*.zip
+*.txt
+*.md
+*.json
+
+# Keep only qwen3_6_scripts/ computility-run.yaml Dockerfile