docs: (#2308) update Node.js version requirement in README

[latenighthackathon]

Description

The README system requirements section lists Node.js v16.0.0 as the minimum version, but the project actually requires Node.js 18+:

• .nvmrc specifies v18
• All package.json engines fields require >=18
• CI runs against Node 18, 20, and 22
• Node 16 has been EOL since September 2023

Updated to Node.js v18 or newer. npm v8 or newer. to match the actual project configuration.

Related Issues

Ref #2308

Testing

Confirm the issue (before the fix)

1. Verify README says Node 16:

grep "Node.js" README.md
# Expected on canary: "Node.js v16.0.0 or newer"

2. Verify actual requirement is Node 18:

cat .nvmrc
# Expected: v18

grep -A 2 '"engines"' package.json
# Expected: "node": ">=18"

Confirm the fix

3. Verify README now matches package.json:

grep "Node.js" README.md
# Expected: "Node.js v18 or newer. npm v8 or newer."

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[changeset-bot]

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Latest commit: 6be3257

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[headless-platform-by-wp-engine]

Currently, we do not support the creation of preview deployments based on changes coming from forked repositories.
Learn more about preview environments in our documentation.