feat: add T-Head PPU runtime backend

[spike-zhu]

Summary

• Add the T-Head PPU backend option through WITH_THEAD.
• Add infini::rt::Device::Type::kThead and runtime dispatch support.
• Add the Thead PPU runtime implementation under src/native/cuda/thead/.

Motivation

InfiniCore previously used an in-tree runtime for Ali PPU. This change adds the required Ali PPU runtime infrastructure to InfiniRT, aligned with existing CUDA-like backends.

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)
• T-Head（WITH_THEAD）
• Build system / CMake / generated headers
• Public headers / installed consumer API
• Documentation only

Smoke Build and Test Result

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

InfiniCore now uses the standalone InfiniRT implementation instead of its in-tree Ali PPU runtime, with InfiniLM test:

[voltjia]

看了一下，没啥太大问题。后面应该就是按照刚才飞书上讨论的，把名称统一改成 ”T-Head“ 和 Thead 吧。

[spike-zhu]

看了一下，没啥太大问题。后面应该就是按照刚才飞书上讨论的，把名称统一改成 ”T-Head“ 和 Thead 吧。

已修改

[voltjia]

PR 描述里好像出现了几处 WITH_Thead，这个应该是全大写的，也就是 WITH_THEAD，不过反而是代码里没发现 hhh，改一下描述吧。

[spike-zhu]

PR 描述里好像出现了几处 WITH_Thead，这个应该是全大写的，也就是 WITH_THEAD，不过反而是代码里没发现 hhh，改一下描述吧。

已调整