[sirreal]

Upgrades the 5.6 branch to Node.js 24.x and npm 11.x. Also:

• Runs Grunt with --no-maglev --no-concurrent-sparkplug, as r63771 does on trunk, to avoid hangs at exit on Node.js 24.
• Runs Grunt with --openssl-legacy-provider, because webpack 4 hashes with md4, which OpenSSL 3 disables.
• Regenerates package-lock.json with npm 11, whose npm ci rejects the npm 6 lockfile's entry for jquery-color, and sets legacy-peer-deps = true in .npmrc so npm 11 resolves peer dependencies as npm 6 did. No package versions change.
• Overrides node-sass (a dependency of @wordpress/scripts 12) with sass, because node-sass 4.14.1 does not compile on Node.js 24. The build does not use it.

Trac ticket: https://core.trac.wordpress.org/ticket/66636

Use of AI Tools

AI assistance: Yes
Tool(s): Claude Code
Model(s): Claude Opus 5.5
Used for: Applying the changes to each branch, regenerating the lockfile, building on Node.js 24 and comparing the output with the release, and drafting this description.

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This Pull Request is for code review only. Please keep all other discussion in the Trac ticket. Do not merge this Pull Request. See GitHub Pull Requests for Code Review in the Core Handbook for more details.

[github-actions]

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[github-actions]

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