media_port defaulted to 0 (OS-assigned) and --port only set the TCP bind_port,
so the UDP relay bound a random high port and advertised it to clients in HELLO.
Self-hosters forwarding only 8384/udp saw connect-OK-but-no-voice, contradicting
docs/deployment.md (control and media share one port). Media now follows
bind_port when media_port is unset; 0=OS-assigned survives when bind_port is also
0 so ephemeral-port tests are unaffected. Banner now reads TCP :8384 UDP :8384.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>