Make StartConfig listener creation context-aware

[EricGusmao]

Summary

• Create listeners with net.ListenConfig so StartConfig respects the provided context during listener setup
• Keep the existing serving behavior by defaulting ListenerNetwork to tcp and wrapping TLS listeners with
  tls.NewListener
• simplify the listener creation path by using the same flow for TLS and non-TLS listeners

Benefit

StartConfig.Start and StartConfig.StartTLS already accept a context, but listener creation previously used net.Listen
and tls.Listen, which do not use that context. This change makes listener setup context-aware without changing how the
server behaves after the listener is created.