migrate to node-version file, use corepack in actions to manage pnpm

[josefaidt]

Motivation and Context

ref #1537, 5 & 14

Migrates the project to use a .node-version file, including migrating GitHub Action workflows to use this file to install the relevant Node.js version. It also migrates the workflows to use corepack to manage pnpm versions instead of the dedicated pnpm setup action.

How Has This Been Tested?

n/a

Breaking Changes

n/a

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)
• Documentation update

Checklist

• I have read the MCP Documentation
• My code follows the repository's style guidelines
• New and existing tests pass locally
• I have added appropriate error handling
• I have added or updated documentation as needed

Additional context

[changeset-bot]

⚠️ No Changeset found

Latest commit: d557446

Merging this PR will not cause a version bump for any packages. If these changes should not result in a new version, you're good to go. If these changes should result in a version bump, you need to add a changeset.

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[pkg-pr-new]

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@modelcontextprotocol/client

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@modelcontextprotocol/server

npm i https://pkg.pr.new/modelcontextprotocol/typescript-sdk/@modelcontextprotocol/server@1538

@modelcontextprotocol/express

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@modelcontextprotocol/hono

npm i https://pkg.pr.new/modelcontextprotocol/typescript-sdk/@modelcontextprotocol/hono@1538

@modelcontextprotocol/node

npm i https://pkg.pr.new/modelcontextprotocol/typescript-sdk/@modelcontextprotocol/node@1538

commit: d557446