Bump Node version to v22.18.0

[github-actions]

The Node version used in the latest version of VS Code has been updated. This PR updates the Node version used for integration tests to match.
The previous Node version was v22.17.0. This PR updates the Node version to v22.18.0.

[Copilot]

Pull Request Overview

Updates Node.js version from v22.17.0 to v22.18.0 to align with the latest version used in VS Code for integration testing.

• Node.js engine requirement updated in package.json
• Node.js type definitions updated to match new version
• NVM configuration updated for consistent development environment

Reviewed Changes

Copilot reviewed 2 out of 3 changed files in this pull request and generated no comments.

File	Description
extensions/ql-vscode/package.json	Updates Node.js engine requirement and @types/node dependency to v22.18.0
extensions/ql-vscode/.nvmrc	Updates NVM Node.js version specification to v22.18.0

Files not reviewed (1)

• extensions/ql-vscode/package-lock.json: Language not supported

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