1. 1. Purpose
      See https://github.com/vllm-project/vllm/issues/20283#event-20038024543
      The purpose of this PR is to perform variable name changes and deprecation warnings for compilation level to compilation mode. Enum values names are also changed. No true changes of behavior nor breaking changes have occurred.

1. 1. Test Plan

1. 1. Test Result

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<details>
<summary> Essential Elements of an Effective PR Description Checklist </summary>

• [ ] 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.
• [ ] (Optional) Release notes update. If your change is user facing, please update the release notes draft in the [Google Doc](https://docs.google.com/document/d/1YyVqrgX4gHTtrstbq8oWUImOyPCKSGnJ7xtTpmXzlRs/edit?tab=t.0).
  </details>