fix(rest/nodejs): support Node.js 24

[tianyubing-tiktok]

Description

The Node.js REST sample documented support for Node.js 20 or newer, but npm ci failed on Node.js 24 because better-sqlite3 9.x could not install a compatible native binary.

• Upgrade better-sqlite3 to 12.11.1, the latest 12.x release supporting Node.js 20, 22, and 24.
• Declare the supported Node.js versions in package.json.
• Run the Node.js workflow against Node.js 20, 22, and 24.
• Pin the workflow's third-party Actions to immutable commit SHAs.
• Align the README prerequisite with the tested versions.

Category (Required)

• Core Protocol: Changes to the base communication layer, global context, or breaking refactors. (Requires Technical Council approval)
• Governance/Contributing: Updates to GOVERNANCE.md, CONTRIBUTING.md, or CODEOWNERS. (Requires Governance Council approval)
• Capability: New schemas (Discovery, Cart, etc.) or extensions. (Requires Maintainer approval)
• Documentation: Updates to README, or documentations regarding schema or capabilities. (Requires Maintainer approval)
• Infrastructure: CI/CD, Linters, or build scripts. (Requires DevOps Maintainer approval)
• Maintenance: Version bumps, lockfile updates, or minor bug fixes. (Requires DevOps Maintainer approval)
• SDK: Language-specific SDK updates and releases. (Requires DevOps Maintainer approval)
• Samples / Conformance: Maintaining samples and the conformance suite. (Requires Maintainer approval)
• UCP Schema: Changes to the ucp-schema tool (resolver, linter, validator). (Requires Maintainer approval)
• Community Health (.github): Updates to templates, workflows, or org-level configs. (Requires DevOps Maintainer approval)

Related Issues

None. No open issue or PR currently covers the Node.js REST sample's Node.js 24 dependency compatibility.

Checklist

• I have followed the Contributing Guide (including Conventional Commits title requirements and ! for breaking changes).
• I have updated the documentation (if applicable).
• My changes pass all local linting and formatting checks.
• I have added tests that prove my fix is effective or that my feature works.
• New and existing unit tests pass locally with my changes.
• (For Core/Capability) I have included/updated the relevant JSON schemas.
• I have regenerated Python Pydantic models by running generate_models.sh under python_sdk.

Verification

• Node.js 24.1.0: npm ci, npm run build, and npm test (116 passing)
• Node.js 22.22.2: npm ci, npm run build, and npm test (116 passing)
• Node.js 20: covered by the added GitHub Actions matrix job