[UX] Move Dockerfile DeepGEMM install to tools/install_deepgemm.sh

[mgoin]

Purpose

Now that we are installing DeepGEMM from source in our Dockerfile, we should pull out the logic into a reusable script for users that are using vllm wheels rather than images.

Test Plan

Tested locally on H100 with my dev vLLM env and installing using

> uv venv --python 3.12 ~/venvs/vllm
> source ~/venvs/vllm/bin/activate
> VLLM_USE_PRECOMPILED=1 uv pip install -U -e . --torch-backend=cu128
> ./tools/install_deepgemm.sh
...
Installing DeepGEMM wheel using uv...
Using Python 3.12.11 environment at: /home/mgoin/venvs/vllm
Resolved 1 package in 7ms
Prepared 1 package in 143ms
Installed 1 package in 18ms
 + deep-gemm==2.0.0+7b6b556 (from file:///home/mgoin/code/vllm/deepgemm/dist/deep_gemm-2.0.0+7b6b556-cp312-cp312-linux_x86_64.whl)
~/code/vllm
✅ DeepGEMM installation completed successfully

Test Result

(Optional) Documentation Update

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Essential Elements of an Effective PR Description Checklist

• The purpose of the PR, such as "Fix some issue (link existing issues this PR will resolve)".
• The test plan, such as providing test command.
• The test results, such as pasting the results comparison before and after, or e2e results
• (Optional) The necessary documentation update, such as updating supported_models.md and examples for a new model.

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[gemini-code-assist]

Code Review

This pull request refactors the DeepGEMM installation logic from the Dockerfile into a separate, reusable shell script. This is a good improvement for modularity and reusability. My review focuses on the new script, tools/install_deepgemm.sh, and I've identified a critical issue with argument parsing and a high-severity issue regarding safe directory handling for the build process. Addressing these will make the script more robust and reliable for both Docker builds and local use.

[yewentao256]

Thanks for the work!

[yewentao256]

LGTM, thanks for the work!