[INFRA] Import NVIDIA/CCCL upstream as optimization reference library

CCCL (CUDA C++ Core Libraries) provides:
- CUB: device/block/warp-level GPU primitives (reduce, scan, sort, topk)
- Thrust: high-level parallel algorithms (transform_reduce, sort, scan)
- libcudacxx: CUDA C++ standard library (atomics, barriers, memory)
- cudax: experimental features (memory resources, allocators)
- Tuning policies: per-SM hardware-specific algorithm parameters

Competition optimization vectors mapped to CCCL:
- Output TPS (83% weight): warp_reduce, block_reduce, device_topk
- Input TPS (14% weight): device_scan, block_load, prefetch
- Cache TPS (3% weight): prefix caching strategy patterns
- Memory (0.9 util): pooled/cached/buddy allocators

Source: https://github.com/NVIDIA/cccl (shallow clone, HEAD only)
License: Apache-2.0

cccl_upstream/thrust/examples/print_version.cu

@@ -0,0 +1,15 @@
+#include <thrust/version.h>
+
+#include <iostream>
+
+int main()
+{
+  int major    = THRUST_MAJOR_VERSION;
+  int minor    = THRUST_MINOR_VERSION;
+  int subminor = THRUST_SUBMINOR_VERSION;
+  int patch    = THRUST_PATCH_NUMBER;
+
+  std::cout << "Thrust v" << major << "." << minor << "." << subminor << "-" << patch << '\n';
+
+  return 0;
+}