Switch every vpc.* producer (domains/ec2/vpc, eip, instance, natgw,
routetable, igw, handlers/elbv2, handlers/eks, daemon, systemvpc) and the
network/subscribers consumer onto contracts/network/v1 subjects, event
types and the shared AckEnvelope. contracts/network/v1 becomes the sole
owner of vpc.igw-attach/detach, replacing the duplicate definitions in
contracts/ec2/v1.
Deletes the duplicated local subject constants and event structs:
subscribers' Topic* consts and event structs, vpc.NATEvent and SGEvent,
eip's natEvent, natgw's natGatewayEvent, and eks's systemEgressEvent.
domains/ec2/vpc.SGRule survives because EC2 persists it directly in
SecurityGroupRecord; contracts/network/v1.SecurityGroupRule was expanded
in slice 2 to match it field-for-field so wire bytes are unchanged.
No lifecycle or reliability changes: the NAT add barrier, delete
retry-on-ErrNoResponders, and the inconsistent per-call-site NAT
delivery modes (EIP AssociateAddress and DeleteNetworkInterface both stay
fire-and-forget with no ack) are preserved exactly, as are the golden
wire literals pinned in the characterization tests.
Declare the versioned wire vocabulary for the vpc.* control-plane-to-
network-realisation boundary: subjects, payload types, the shared
{success,error} ack envelope and the vpcd-workers queue group, one
file per route family. No NATS I/O, no consumer switched over yet;
the package coexists with the fragmented originals pinned in the
prior characterization commit until slice 3 migrates call sites.
joshsiv-mulga