server: (UI) add syntax highlighting and latex math rendering (#10808)
* add code highlighting and math formatting
* code cleanup
* build public/index.html
* rebuild public/index.html
* fixed coding style
* fixed coding style
* style fixes
* highlight: smaller bundle size, fix light & dark theme
* remove katex
* add bundle size check
* add more languages
* add php
* reuse some langs
* use gzip
* Revert "remove katex"
This reverts commit c0e5046accd10be3f83018cffdc29a652849fc61.
* use better maintained @vscode/markdown-it-katex
* fix gzip non deterministic
* ability to add a demo conversation for dev
* fix latex rendering
* add comment
* latex codeblock as code
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Co-authored-by: Xuan Son Nguyen <[email protected]>
