Glorious Network Stack Rewrite (using my own brain and hands this time)

[FlareCoding]

Note

High Risk
Full rewrite of kernel networking and driver/stack boundaries; only virtio-net is registered, so hardware Ethernet paths lose DHCP and stack connectivity until re-integrated.

Overview
Replaces the old netif callback + deferred TX/DHCP model with a packet / interface stack: drivers hand frames in through receive(), layers use eth → ipv4 → ICMP/ARP, and netstkd ages the ARP table. Virtio-net is the only driver wired end-to-end today—it subclasses net::interface, registers as ethN, copies RX into packets, and transmits via transmit(packet*) with a temporary QEMU static IPv4 config.

BCM GENET and RTL8168 are stripped back to link-layer only: embedded m_mac, instance transmit(frame), no register_netif, no DHCP/link callbacks, and RX no longer feeds the stack (placeholder until a protocol stack attaches). The monolithic inet_socket, dhcp, loopback, and ethernet modules are removed in favor of eth, typed ipv4/eth addresses, refactored checksum/byteorder, non-blocking ARP with pending packet queues, and ICMP ping sockets via inet::create_socket. UDP/TCP are not carried forward yet—IPv4 logs and drops them. Style rules add documentation voice guidance using interface.h as the reference.

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