Fix/sglang kt detection (#1875)

* [feat]: simplify sglang installation with submodule, auto-sync CI, and version alignment

- Add kvcache-ai/sglang as git submodule at third_party/sglang (branch = main)
- Add top-level install.sh for one-click source installation (sglang + kt-kernel)
- Add sglang-kt as hard dependency in kt-kernel/pyproject.toml
- Add CI workflow to auto-sync sglang submodule daily and create PR
- Add CI workflow to build and publish sglang-kt to PyPI
- Integrate sglang-kt build into release-pypi.yml (version.py bump publishes both packages)
- Align sglang-kt version with ktransformers via SGLANG_KT_VERSION env var injection
- Update Dockerfile to use submodule and inject aligned version
- Update all 13 doc files, CLI hints, and i18n strings to reference new install methods

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

* [build]: bump version to 0.5.2

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

* [build]: rename PyPI package from kt-kernel to ktransformers

Users can now `pip install ktransformers` to get everything
(sglang-kt is auto-installed as a dependency).

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

* Revert "[build]: rename PyPI package from kt-kernel to ktransformers"

This reverts commit e0cbbf6364.

* [build]: add ktransformers meta-package for PyPI

`pip install ktransformers` now works as a single install command.
It pulls kt-kernel (which in turn pulls sglang-kt).

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

* [fix]: show sglang-kt package version in kt version command

- Prioritize sglang-kt package version (aligned with ktransformers)
  over sglang internal __version__
- Update display name from "sglang" to "sglang-kt"

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

* [fix]: improve sglang-kt detection in kt doctor and kt version

Recognize sglang-kt package name as proof of kvcache-ai fork installation.
Previously both commands fell through to "PyPI (not recommended)" for
non-editable local source installs. Now version.py reuses the centralized
check_sglang_installation() logic.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

* [build]: bump version to 0.5.2.post1

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

---------

Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>

kt-kernel/README_zh.md

@@ -115,12 +115,23 @@ KT-Kernel 可以单独通过 [Python API](#直接使用-python-api) 使用，也
 
 #### 1. 安装 SGLang
 
+安装 kvcache-ai 分支的 SGLang（kt-kernel 需要此分支）：
+
 ```bash
-git clone https://github.com/sgl-project/sglang.git
-cd sglang
-pip install -e "python[all]"
+# 方式 A: 一键安装（从 ktransformers 根目录，同时安装 sglang + kt-kernel）
+./install.sh
+
+# 方式 B: pip 安装
+pip install sglang-kt
+
+# 方式 C: 从源码安装（可编辑模式）
+git clone --recursive https://github.com/kvcache-ai/ktransformers.git
+cd ktransformers
+pip install -e "third_party/sglang/python[all]"
 ```
 
+> **重要:** 请使用 `sglang-kt`（kvcache-ai 分支），而非官方 `sglang` 包。如已安装官方版本，请先卸载：`pip uninstall sglang -y`
+
 #### 2. 准备权重
 
 要进行异构推理，需要同时准备 GPU 权重和 CPU 侧 experts 对应的权重，具体格式取决于后端类型：