(feat) Enable Tex in markdown

[igor-kramer]

Datahub uses @uiw/react-md-editor for Markdown rendering. Please enable Tex support via katex.
https://uiwjs.github.io/react-md-editor/#support-custom-katex-preview

[coderabbitai]

A summary of the changes CodeRabbit can apply:

• Enable KaTeX math rendering across DataHub markdown by adding the "katex" dependency to datahub-web-react/package.json, updating legacy MarkdownViewer.tsx to use KaTeX rehype plugins, adding Remirror KaTeX extension files (KaTeXExtension.tsx, KaTeXComponent.tsx, README) under alchemy-components, injecting the KaTeX extension into Editor.tsx (both alchemy and entity-specific editor paths), and updating markdownToHtml.tsx converters to handle inline $...$ and block math/latex math—so markdown now supports rendered math (requires npm/yarn install and server restart).

• Add KaTeX math rendering support by adding the katex dependency to package.json; adding a Remirror KaTeX node extension (KaTeXExtension.tsx) and node view component (KaTeXComponent.tsx) plus README; injecting the KaTeXExtension into Editor.tsx files in two editor locations; and enabling KaTeX rendering in markdown/html paths by updating markdownToHtml.tsx and MarkdownViewer.tsx (rehype plugin) to render inline ($...$) and block (math/latex) math, and updating markdownToHtml return handling.

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