Laguna M.1 support now ships in SGLang's nightly wheels (0.5.14.dev20260618+ and later, which include the global-attention and attention-gate `quant_config` fixes), so the README can install from the nightly index instead of cloning and building SGLang from source.
Replaces the `git clone` + `pip install -e "python[all]"` block with:
`pip install sglang --pre --extra-index-url https://sgl-project.github.io/whl/cu129/`
