Improvement: Detect port-in-use before starting services #40
Description
TL;DR
The launcher does not check if ports 5115 or 3000 are already in use before starting services.
Current State
If a port is occupied, the launcher may show "OK" but the service is unreachable. No clear error.
Desired State
Check port availability before launching. Show a clear message if a port is already in use.