feat: add graph runtime API

[gongchensu]

Summary

• Adds generated C++ runtime declarations and dispatch support for stream capture and graph lifecycle APIs in scripts/generate_public_headers.py.
• Adds native graph API coverage for CUDA-like backends in src/native/cuda/nvidia/runtime_.h, src/native/cuda/iluvatar/runtime_.h, and src/native/cuda/ascend/runtime_.h.
• Adds an adaptive graph runtime test in tests/test_native_graph.cc, wired through tests/CMakeLists.txt.

Motivation

InfiniRT should expose CUDA Runtime API-aligned graph capture and graph launch APIs through the generated C++ runtime API, without introducing a C API. This is needed by the standalone InfiniRT graph bridge work in InfiniCore.

Related: InfiniTensor/InfiniCore#1351

Type of Change

• feat - new feature / new operator / new platform
• fix - bug fix
• perf - performance improvement (no behavioral 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)
• MetaX (WITH_METAX)
• Cambricon (WITH_CAMBRICON)
• Moore (WITH_MOORE)
• Ascend (WITH_ASCEND)
• PyTorch C++ bindings (WITH_TORCH)
• Build system / CMake / CI
• Python bindings / user-facing API

Smoke Test Result

# ssh nvidia, image: infinirt-verify:nvidia-latest
clang-format --dry-run --Werror include/infini/rt.h tests/test_native_graph.cc
cmake -B build \
-DWITH_CPU=ON \
-DWITH_NVIDIA=ON \
-DINFINI_RT_BUILD_TESTING=ON \
-DCMAKE_BUILD_TYPE=Release \
-DCMAKE_INSTALL_PREFIX=/workspace/infini-rt-prefix
cmake --build build -j$(nproc)
ctest --test-dir build --output-on-failure
100% tests passed, 0 tests failed out of 8
Passed tests include test_nvidia_graph and test_runtime_dispatch.

Test Results on Supported Platforms

Platform	Affected	Build / Smoke Result	Full Result / Notes
NVIDIA	Yes	smoke passed	ctest passed: 8/8
Iluvatar	Yes	not run	No Iluvatar validation in this round
MetaX	No	not run	N/A
Cambricon	No	not run	N/A
Moore	No	not run	N/A
Ascend	Yes	not run	No Ascend validation in this round

Full `pytest` output (optional)

N/A

Benchmark / Performance Impact

N/A. This PR adds runtime API surface and tests; it does not tune kernel performance.

Notes for Reviewers

• This PR intentionally keeps InfiniRT as C++ API only. No C API is added.
• The public runtime graph API is generated under infini::rt::runtime.