docs: add Node.js prerequisites to local installation options

- Added Node.js prerequisite for Option 2: Local Installation (any version)
- Added Node.js 18+ prerequisite for Option 3: Remote Server
- Added prerequisites section to Local Development Setup
- Clarified that any Node.js version works for local installation due to automatic fallback

This ensures users know they need Node.js installed before attempting local installations.

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <noreply@anthropic.com>

README.md

@@ -149,6 +149,8 @@ See Quick Start above for the simplest setup.
 ### Option 2: Local Installation
 If you prefer running locally:
 
+**Prerequisites:** [Node.js](https://nodejs.org/) installed on your system (any version)
+
 ```json
 {
   "mcpServers": {
@@ -171,6 +173,8 @@ If you prefer running locally:
 
 For team deployments:
 
+**Prerequisites:** [Node.js](https://nodejs.org/) 18+ installed locally (for mcp-http-client)
+
 ```json
 {
   "mcpServers": {
@@ -197,6 +201,11 @@ For team deployments:
 
 For contributors and advanced users:
 
+**Prerequisites:**
+- [Node.js](https://nodejs.org/) (any version - automatic fallback if needed)
+- npm or yarn
+- Git
+
 ```bash
 # 1. Clone the repository
 git clone https://github.com/czlonkowski/n8n-mcp.git