fix(systemd): use Type=forking for background start.sh compatibility

- Change Type=simple to Type=forking in systemd service
- Properly handle start.sh background process (&)
- Ensures systemd correctly tracks daemon lifecycle
- Fixes BSD-compatible start script integration

Fixes #104

deployment/linux/furt.service

@@ -3,7 +3,7 @@ Description=furt Multi-Tenant API Gateway
 After=network.target
 
 [Service]
-Type=simple
+Type=forking
 User=furt
 Group=furt
 ExecStart=/usr/local/share/furt/scripts/start.sh start