65c8e932e2
Port 80 features from server/events.go including the full events infrastructure: internal send/receive loops, system subscription machinery, statsz heartbeats, remote server tracking, connection event advisories, user-info handler, OCSP peer reject events, remote latency merge, kick/ldm client, and helper functions. Add ClearConnectionHeartbeatTimer/SetConnectionHeartbeatTimer to Account, add MsgHandler/SysMsgHandler delegates and supporting types (ServerApiResponse, EventFilterOptions, StatszEventOptions, UserInfo, KickClientReq, LdmClientReq, AccNumSubsReq) to EventTypes.cs, and add Seq field to ServerInfo for heartbeat sequence tracking.