Log actual TcpListener local addresses for clarity

[DOCtorActoAntohich]

consider the following minimal config

[rtmp]
enabled = true
port = 0

# for simplicity, let's imagine rtsp and other stuff is just disabled

[httpapi]
port = 0

specifying port 0 means the system will assign any free port. this is cool and all but the logs don't reflect the truth

$ xiu --config the-config-from-above.toml
[2026-04-28T07:43:58Z INFO  rtmp::rtmp] Rtmp server listening on tcp://0.0.0.0:0
[2026-04-28T07:43:58Z INFO  xiu::api] Http api server listening on http://0.0.0.0:0

this is just wrong information because: we can't actually bind to port 0, and we can't have two sockets on one port.

instead, here's the truth:

lsof -i -P | grep xiu
xiu       89412  doc    9u  IPv4 0xccdde83db1f0d39a      0t0    TCP *:60689 (LISTEN)
xiu       89412  doc   10u  IPv4 0xa36499b626ff5706      0t0    TCP *:60690 (LISTEN)

so as we see, the system properly assigns the ports, but logs don't reflect it.

the fix is simple: instead of printing the info from the config, we can show the actual port the TcpListener binds to

this change can make the app more automation-friendly...

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also no reason to parse SocketAddr from string when you know you can use the UNSPECIFIED address, and the port is already given