The UID introduction omitted the second user field (insp sends both a real and a
displayed user), and the parser didn't strip IRCv3 message-tag prefixes, so
tagged PRIVMSGs addressed to a service were dropped. With both fixed a service
links to a real insp4 uplink and answers commands. Adds an irctest services
controller so this is verified against an isolated, throwaway ircd.
Protocol-agnostic core: a Protocol trait maps raw server-to-server lines to a
normalized event/action model, so the engine never touches a raw line and a new
ircd is one new module. Adds event-log state (state is a fold over the log) and
a service framework. First protocol impl links to an InspIRCd (insp4) uplink —
completes the CAPAB/SERVER handshake, bursts, and introduces NickServ.
