Add Docker deployment and Apache reverse proxy setup

🐳 Docker Implementation:
- Add Dockerfile with Alpine Linux (46MB image)
- Add docker-compose.yml with production-ready config
- Add manage-relay.sh for easy local management
- Add stella-relay.service for systemd auto-start
- Published images: silberengel/orly-relay:latest, :v1, :v2

🔧 Apache Reverse Proxy:
- Add comprehensive Apache proxy guide for Plesk and standard Apache
- Add working WebSocket proxy configuration (ws:// not http://)
- Add troubleshooting guide based on real deployment experience
- Add debug-websocket.sh script for systematic diagnosis

WEBSOCKET-DEBUG.md

@@ -0,0 +1,109 @@
+# WebSocket Connection Debug Guide
+
+## 🚨 **Current Issue**
+`wss://orly-relay.imwald.eu/` returns `NS_ERROR_WEBSOCKET_CONNECTION_REFUSED`
+
+## 🔍 **Debug Steps**
+
+### **Step 1: Verify Relay is Running**
+```bash
+# On your server
+curl -I http://127.0.0.1:7777
+# Should return: HTTP/1.1 426 Upgrade Required
+
+docker ps | grep stella
+# Should show running container
+```
+
+### **Step 2: Test Apache Modules**
+```bash
+# Check if WebSocket modules are enabled
+apache2ctl -M | grep -E "(proxy|rewrite)"
+
+# If missing, enable them:
+sudo a2enmod proxy
+sudo a2enmod proxy_http
+sudo a2enmod proxy_wstunnel
+sudo a2enmod rewrite
+sudo a2enmod headers
+sudo systemctl restart apache2
+```
+
+### **Step 3: Check Apache Configuration**
+```bash
+# Check what Plesk generated
+sudo cat /etc/apache2/plesk.conf.d/vhosts/orly-relay.imwald.eu.conf
+
+# Look for proxy and rewrite rules
+grep -E "(Proxy|Rewrite)" /etc/apache2/plesk.conf.d/vhosts/orly-relay.imwald.eu.conf
+```
+
+### **Step 4: Test Direct WebSocket Connection**
+```bash
+# Test if the issue is Apache or the relay itself
+echo '["REQ","test",{}]' | websocat ws://127.0.0.1:7777/
+
+# If that works, the issue is Apache proxy
+# If that fails, the issue is the relay
+```
+
+### **Step 5: Check Apache Error Logs**
+```bash
+# Watch Apache errors in real-time
+sudo tail -f /var/log/apache2/error.log
+
+# Then try connecting to wss://orly-relay.imwald.eu/ and see what errors appear
+```
+
+## 🔧 **Specific Plesk Fix**
+
+Based on your current status, try this **exact configuration** in Plesk:
+
+### **Go to Apache & nginx Settings for orly-relay.imwald.eu:**
+
+**Clear both HTTP and HTTPS sections, then add to HTTPS:**
+
+```apache
+# Enable proxy
+ProxyRequests Off
+ProxyPreserveHost On
+
+# WebSocket handling - the key part
+RewriteEngine On
+RewriteCond %{HTTP:Upgrade} =websocket [NC]
+RewriteCond %{HTTP:Connection} upgrade [NC]
+RewriteRule /(.*) ws://127.0.0.1:7777/$1 [P,L]
+
+# Fallback for regular HTTP
+RewriteCond %{HTTP:Upgrade} !=websocket [NC]
+RewriteRule /(.*) http://127.0.0.1:7777/$1 [P,L]
+
+# Headers
+ProxyAddHeaders On
+```
+
+### **Alternative Simpler Version:**
+If the above doesn't work, try just:
+
+```apache
+ProxyPass / http://127.0.0.1:7777/
+ProxyPassReverse / http://127.0.0.1:7777/
+ProxyPass /ws ws://127.0.0.1:7777/
+ProxyPassReverse /ws ws://127.0.0.1:7777/
+```
+
+## 🧪 **Testing Commands**
+
+```bash
+# Test the WebSocket after each change
+echo '["REQ","test",{}]' | websocat wss://orly-relay.imwald.eu/
+
+# Check what's actually being served
+curl -v https://orly-relay.imwald.eu/ 2>&1 | grep -E "(HTTP|upgrade|connection)"
+```
+
+## 🎯 **Expected Fix**
+
+The issue is likely that Apache isn't properly handling the WebSocket upgrade request. The `proxy_wstunnel` module and correct rewrite rules should fix this.
+
+Try the **simpler ProxyPass version first** - it's often more reliable in Plesk environments.