Fix install instructions and pyproject.tomls (#11781)

docs/get_started/install.md

@@ -12,7 +12,7 @@ It is recommended to use uv for faster installation:
 ```bash
 pip install --upgrade pip
 pip install uv
-uv pip install sglang --upgrade
+uv pip install sglang --prerelease=allow
 ```
 
 **Quick fixes to common problems**
@@ -129,5 +129,3 @@ sky status --endpoint 30000 sglang
 
 - [FlashInfer](https://github.com/flashinfer-ai/flashinfer) is the default attention kernel backend. It only supports sm75 and above. If you encounter any FlashInfer-related issues on sm75+ devices (e.g., T4, A10, A100, L4, L40S, H100), please switch to other kernels by adding `--attention-backend triton --sampling-backend pytorch` and open an issue on GitHub.
 - To reinstall flashinfer locally, use the following command: `pip3 install --upgrade flashinfer-python --force-reinstall --no-deps` and then delete the cache with `rm -rf ~/.cache/flashinfer`.
-- If you only need to use OpenAI API models with the frontend language, you can avoid installing other dependencies by using `pip install "sglang[openai]"`.
-- The language frontend operates independently of the backend runtime. You can install the frontend locally without needing a GPU, while the backend can be set up on a GPU-enabled machine. To install the frontend, run `pip install sglang`, and for the backend, use `pip install sglang[srt]`. `srt` is the abbreviation of SGLang runtime.