Fix Node.js version compatibility mismatch for Ghost 6.0

[erinmikailstaples]

Problem

The Ghost CLI had a version mismatch between its reported Node.js compatibility and Ghost 6.0's actual requirements:
CLI reported support: Node.js ^22.11.0 (in package.json)
Ghost 6.0 actual requirement: Node.js ^22.13.1
This caused a confusing user experience where:
✅ CLI would say "Node.js v22.11.0 is supported"
❌ But then fail during installation with "Ghost v6.0.1 requires Node.js ^22.13.1"

Files Changed

• package.json - Updated Node.js engine requirements
• README.md - Added comprehensive Node.js requirements section

Solution

Updated the package.json engine requirements from:
"node": "^12.22.1 || ^14.17.0 || ^16.13.0 || ^18.0.0 || ^20.11.1 || ^22.11.0"
To:
"node": "^12.22.1 || ^14.17.0 || ^16.13.0 || ^18.0.0 || ^20.11.1 || ^22.13.1"

Additionally added the required node versions in the README:

## Node.js Requirements

Ghost-CLI requires Node.js to be installed on your system. The following Node.js versions are supported:

- **Node.js 12.x**: `^12.22.1` or higher
- **Node.js 14.x**: `^14.17.0` or higher  
- **Node.js 16.x**: `^16.13.0` or higher
- **Node.js 18.x**: `^18.0.0` or higher
- **Node.js 20.x**: `^20.11.1` or higher
- **Node.js 22.x**: `^22.13.1` or higher

> **Important**: For Ghost 6.0+, Node.js 22.13.1 or higher is required. Earlier versions of Node.js 22.x (like 22.11.0) are not compatible.

You can check your Node.js version by running:
```bash
node --version

Impact:

This fix ensures:

• Users get accurate Node.js version requirements upfront
• No more misleading "compatible" messages followed by installation failures
• The CLI's compatibility check matches Ghost's actual requirements
• Users can confidently install Node.js v22.13.1+ knowing it will work with Ghost 6.0