feat(hygon): add graph runtime support

[gongchensu]

Summary

• Extend Runtime<Device::Type::kHygon> with InfiniRT's GraphRuntime interface.
• Expose DTK graph capture, instantiate, launch, and cleanup operations.
• Add test_hygon_graph to validate native Hygon graph capture and replay.

Motivation

The Hygon runtime previously implemented only the common CUDA runtime interface. As a result, upper layers such as InfiniCore could not use the common InfiniRT C++ graph bridge on Hygon devices.

This change exposes DTK's CUDA-compatible graph APIs through the existing InfiniRT GraphRuntime abstraction. It allows Hygon to use the same graph capture and replay path as other supported backends without introducing a backend-specific graph implementation.

No linked issue.

Type of Change

• feat - new feature / new backend capability / new public API
• fix - bug fix
• perf - performance improvement without behavior change
• refactor - code restructuring without behavior change
• test - adding or fixing tests only
• docs - documentation only
• build / ci - build system or CI configuration
• chore - tooling, formatting, or other non-code changes
• Breaking change (requires a ! in the Conventional Commits prefix or a BREAKING CHANGE: footer)

Platforms Affected

• CPU (WITH_CPU)
• NVIDIA (WITH_NVIDIA)
• Iluvatar (WITH_ILUVATAR)
• Hygon (WITH_HYGON)
• MetaX (WITH_METAX)
• Moore (WITH_MOORE)
• Cambricon (WITH_CAMBRICON)
• Ascend (WITH_ASCEND)
• Build system / CMake / generated headers
• Public headers / installed consumer API
• Documentation only

Smoke Build and Test Result

Tested on a Hygon BW DCU with DTK 26.04-rc4.

cmake -S . -B build-hygon \
  -DCMAKE_BUILD_TYPE=Release \
  -DWITH_CPU=ON \
  -DWITH_HYGON=ON \
  -DDTK_ROOT=/opt/dtk \
  -DINFINI_RT_BUILD_TESTING=ON

cmake --build build-hygon --parallel 8

export LD_LIBRARY_PATH=/opt/dtk/cuda/cuda-12/targets/x86_64-linux/lib:$LD_LIBRARY_PATH

ctest \
  --test-dir build-hygon \
  --output-on-failure

```text
paste smoke build and test output here

Test Results on Supported Platforms

Platform	Affected	Build / Smoke Result	Full Result / Notes
CPU
NVIDIA
Iluvatar
Hygon
MetaX
Moore
Cambricon
Ascend

Full `ctest` output (optional)

paste here

Benchmark / Performance Impact

Notes for Reviewers