Optional [gossip.tls] wraps the peer link in TLS: each node presents a
certificate and requires the peer to present one signed by the configured
CA. scripts/gen-certs.sh builds a CA and node certs.
Nodes run anti-entropy over a TCP link: each advertises its version
vector, the peer replies with the log entries it lacks, and ingest is
idempotent so re-delivery and reconnect after a split both converge.
The engine is shared behind a mutex; config gains [gossip] and [[peer]].
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.
