chore: Update README.md

[dep]

I had to do this to get it running.

[czlonkowski]

Request Changes

Thank you for your contribution! However, this change introduces a contradiction in the installation instructions that needs to be addressed.

Issue

The proposed change adds npm install -g n8n-mcp before the npx n8n-mcp command, which defeats the purpose of using npx. The key benefit of npx is that it allows running packages without installation, making the global install step unnecessary and confusing.

Current behavior (correct):

• npx n8n-mcp downloads and runs the package in one step without permanent installation
• This is the recommended approach for quick start guides

Proposed change (problematic):

• Installing globally with npm install -g then using npx is redundant
• The comment "(no installation needed!)" becomes incorrect

Suggestions:

1. Keep the original version - npx n8n-mcp alone is the correct approach
2. If you encountered issues: Please describe the specific error you faced so we can address the root cause
3. Alternative: If we need to document both methods, they should be presented as separate options:

   # Option 1: Run without installation (recommended)
   npx n8n-mcp
   
   # Option 2: Install globally
   npm install -g n8n-mcp
   n8n-mcp

Could you please either revert this change or help us understand what specific issue you encountered that required the global installation? This will help us provide better documentation or fix any underlying problems.