Build/Test Tools: Restore React Refresh scripts for hot reloading

[youknowriad]

Summary

Restores the wp_register_development_scripts() function and associated build infrastructure to enable hot module replacement (HMR) when using @wordpress/scripts with the --hot flag.

The React Refresh scripts were removed in [61438] as part of the Gutenberg build restructuring, but they are still needed for plugin developers using wp-scripts start --hot for block development.

Changes

• Adds react-refresh and @pmmmwh/react-refresh-webpack-plugin npm dependencies
• Creates tools/webpack/development.js to build the development scripts
• Restores wp_register_development_scripts() in script-loader.php
• Removes the deprecated stub from deprecated.php

The scripts are only registered when SCRIPT_DEBUG is true and are not loaded during Core tests.

Trac Ticket

https://core.trac.wordpress.org/ticket/64393

Test Plan

1. Set SCRIPT_DEBUG to true in wp-config.php
2. Create a plugin using @wordpress/scripts
3. Run wp-scripts start --hot
4. Verify hot module replacement works when editing React components

🤖 Generated with Claude Code

[github-actions]

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Props youknowriad.

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[youknowriad]

Hot reloading has proven to be not very valuable in Gutenberg and WordPress in general since it's not a typical SPA. That said, this PR restores the previous behavior so we can make an informed decision about whether we still want it or not.

[github-actions]

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[youknowriad]

I tested this with an example plugin, it works but I understand why no one really uses this, it's not the seamless experience that you get with SPAs. Anyone, we can see whether to commit or not this PR.