Add CRA 5 production build guidance

[PVillarmarzo]

Summary

Adds documentation for the Create React App 5 production-build compatibility issue when consuming Reveal SDK from npm.

Changes

• Added a CRA 5 entry to Known Issues describing the production-build behavior and the validated externals + self-hosted IIFE workaround.
• Added a short warning in Getting Started with React linking to the Known Issues guidance.
• Added a cross-reference in the 2.0 Upgrade Guide for applications migrating from the legacy script-based client to the npm package.

Validation

• git diff --check
• Docusaurus production build completed successfully for English and Japanese.

[zdrawku]

@PVillarmarzo, please address this:

1. Markdown list is broken by the unindented code fences.

The fenced blocks in steps 2 and 3 start at column 0, which closes the ordered list. As rendered, the <script> snippet and the config.externals snippet fall outside the list, and step 3/4 restart numbering at 1. instead of continuing. Indenting the continuation content by 3 spaces keeps them inside their list items:

Suggestions:

• Add the IIFE bundle to public/index.html:

  <script src="%PUBLIC_URL%/reveal/reveal-sdk.js"></script>

• Configure Webpack externals in your CRA override:

  config.externals = {
      ...(config.externals || {}),
      "reveal-sdk": "Reveal",
  };

Same treatment is needed for steps 1 and 4.

2. The CRA override assumes the reader is already on craco or react-app-rewired, but stock CRA has no override hook, so this step is a dead end for them, no? Naming the tool and the file (e.g. craco.config.js via webpack.configure) would make it actionable. @MLopezIG what do you think?

3. Add JP equivalent of your changes please

[PVillarmarzo]

Thanks! I addressed the review feedback and pushed the updates.

Fixed the Markdown list nesting.
Made the CRA override steps actionable using the validated react-app-rewired setup.
Added the Japanese equivalents.

The docs build passes for both EN and JA.