net.nx

net.nx -- BSD-style socket primitives (Phase G2). Typed wrappers around Linux/NishiOS socket syscalls. Fallible public calls return `*Result<i64, NetError>` -- the Ok payload is an fd (for socket / accept) or a byte count (for send / recv) or 0 (for bind / listen / connect). Raw `_raw` variants keep the bare syscall return for callers that want the i64 directly (e.g. tight send loops). Syscall numbers (Linux RV64, NishiOS matches): 198 socket 200 bind 201 listen 202 accept 203 connect 206 sendto (we use as send) 207 recvfrom (we use as recv) 208 setsockopt 209 getsockopt Address families (SOL): AF_INET = 2 (IPv4) AF_INET6 = 10 (IPv6) Socket types: SOCK_STREAM = 1 (TCP) SOCK_DGRAM = 2 (UDP) The typed variant struct SockAddrIn matches Linux's `struct sockaddr_in` exactly (16 bytes): sin_family + sin_port (big- endian) + sin_addr + 8 bytes of padding.