Implement auto-generation of ecosystem.config.js and improve container setup

- Add automatic ecosystem.config.js generation from package.json
- Create app directory automatically if missing
- Copy simple-website example when app directory is empty
- Remove redundant default app files from configs/
- Add HAProxy support with proper real IP forwarding
- Configure nginx to trust proxy headers from private networks
- Simplify entrypoint logic - always use /home/$user/app

This makes the container more user-friendly by eliminating the need for
manual PM2 configuration and ensuring the server always has a working app.

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

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

README.md

@@ -81,7 +81,7 @@ Your Node.js application needs just two files to get started:
 
 **Optional Files:**
 - `public/` folder for static files (HTML, CSS, images)
-- `ecosystem.config.js` for advanced PM2 configuration
+- `ecosystem.config.js` for advanced PM2 configuration (auto-generated if not provided)
 
 ### Step 2: What Users Need to Do
 
@@ -134,10 +134,18 @@ app.listen(port, () => {
 
 **That's it!** The container will:
 - Install your dependencies automatically
+- Generate PM2 configuration from your package.json
 - Start your application with PM2
 - Handle SSL and reverse proxy
 - Provide health monitoring
 
+#### Important package.json fields:
+- **name**: Used as the PM2 process name (defaults to 'node-app')
+- **main**: Entry point file (defaults to 'index.js')
+- **scripts.start**: Alternative way to specify entry point (e.g., "node server.js")
+
+The container automatically generates an ecosystem.config.js file from your package.json if you don't provide one.
+
 ### Step 3: Example Applications
 
 See the `examples/` directory for complete working examples: