Implement socket and networking API

[pbalduino]

Goal

Add Berkeley sockets API to enable network programming with TCP/IP sockets.

Context

No networking API exists yet. This requires both kernel socket infrastructure and userland API.

Definition of Done

• [ ] socket() - Create socket
• [ ] bind() - Bind to address
• [ ] listen() / accept() - Server operations
• [ ] connect() - Client connection
• [ ] send() / recv() / sendto() / recvfrom() - Data transfer
• [ ] sendmsg() / recvmsg() - Advanced I/O
• [ ] shutdown() - Shutdown connection
• [ ] getsockopt() / setsockopt() - Socket options
• [ ] getaddrinfo() / getnameinfo() - Name resolution
• [ ] inet_pton() / inet_ntop() - Address conversion

Dependencies

Required

• #67 - e1000 network driver (or other NIC)
• TCP/IP stack (not yet tracked)

Priority

Low - Future work

Estimated Time

12+ weeks part-time (needs kernel TCP/IP stack first)