build: Proposal to move from webpack to vite

[capistrant]

Description

Draft code inspired by a question from @jtuglu1 #19312 (comment). I took it literally and used a claude session to plan and execute this proposed move to Vite. This was very much an exercise born out of curiosity so I am opening this for CI to run and will put in in Draft as I self review it and look for feedback regarding the webpack versus vite discussion. I did do basic testing locally where I had the vite dev server running locally and was making changes and seeing the millisecond response time from change to seeing it in my local. Even so, a larger discussion is warranted and there would likely be follow ups. The plan my session put in place marked multiple things as bridge solutions to minimize the changeset, but would require follow ups to fully leverage vite.

Release note

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Key changed/added classes in this PR

• vite.config.mts

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This PR has:

• been self-reviewed.
• added documentation for new or modified features or behaviors.
• a release note entry in the PR description.
• added Javadocs for most classes and all non-trivial methods. Linked related entities via Javadoc links.
• added or updated version, license, or notice information in licenses.yaml
• added comments explaining the "why" and the intent of the code wherever would not be obvious for an unfamiliar reader.
• added unit tests or modified existing tests to cover new code paths, ensuring the threshold for code coverage is met.
• added integration tests.
• been tested in a test Druid cluster.

[Fly-Style]

My 50 cents here: vite 8 uses rolldown, which reduces build time for tens of percent.