libSceNet: sceNetListen on an unbound TCP socket fails with EINVAL on Windows; FreeBSD binds the wildcard address and succeeds; fix branch ready #5339

sceNetListen on a TCP socket the guest never bound fails with EINVAL on Windows, because Winsock requires a bound socket before listen. FreeBSD 11.4 tcp_usr_listen calls in_pcbbind when the socket has no local port (inp_lport == 0), which binds the wildcard address with an ephemeral port, so the call succeeds. A server that calls listen first and then reads the port with getsockname (a common way to get a free port) works on the console and fails here.

Fix branch: https://github.com/husseinkad/AnyPS5/tree/fix/net-listen-autobind (two commits on a recent main: the change and a correction from review; libSceNet/Export.cpp and tests/GuestSceNet.cpp with CheckListenWithoutBind for IPv4 and IPv6 and CheckListenAfterRefusedConnect). sceNetListen now binds the wildcard address of the socket's family first, unless the socket was already bound or already has a local port. The first version bound unconditionally and broke a case that worked on main: after a refused TCP connect, Winsock keeps an automatic local port, the extra bind failed with WSAEINVAL, and listen returned EINVAL where main (and FreeBSD) return 0.

Checks:

• The new tests fail on main (abort), and CheckListenAfterRefusedConnect fails on the first version of the branch; both pass on the final head, 6 of 6 runs; guest_sce_net and the datagram tests pass.
• Probed through the guest exports against main, IPv4 and IPv6: a fresh TCP socket now listens (main EINVAL), 50 concurrent listeners each got a distinct nonzero ephemeral port, and connect and accept to the auto-bound port work. Matches FreeBSD: a second listen returns 0, listen on a UDP socket returns EOPNOTSUPP, listen after a failed bind (EADDRNOTAVAIL or EADDRINUSE) returns 0, and backlogs 0, -1, 1, 128, INT_MAX and INT_MIN all return 0. listen on a connected or accepted socket returns EINVAL (main returned 0 or EBADF).
• Two independent reviews found nothing wrong in the final version. check_conventions.py is clean; pr_overlap.py finds only test-file overlap with fix(libSceNet): dissolve a datagram association on connect to AF_UNSPEC #4669 and fix(libSceNet): report SO_ERROR from sceNetGetsockopt #4988 (same insertion points; their Export.cpp hunks are in sceNetConnect and sceNetGetsockopt).

Not covered: the Linux behaviour was read, not run (the host listen already auto-binds there). Only Windows was built and run.

AI-assisted: yes