4e63820e7a
Group A: Create MsgTrace.cs with TraceCompressionType, MsgTraceState (factory methods, pipeline event helpers, sendEvent/sendEventFromJetStream, trace header injection) and MsgTraceHelper (sample, genHeaderMapIfTraceHeadersPresent, initAndSendIngressErrEvent, isMsgTraceEnabled, msgTraceSupport). Adds Trace field to PublishArgument and Trace accessor to ParseContext. Group C: Create MonitorHelpers.cs with GatewayzOptions, Gatewayz, RemoteGatewayz, AccountGatewayz, ExtImport, ExtServiceLatency types; plus 25 standalone helper functions (newSubsDetailList, newSubsList, createProxyInfo, makePeerCerts, decodeBool, decodeUint64, decodeInt, decodeState, decodeSubs, newSubDetail, newClientSubDetail, myUptime, tlsCertNotAfter, urlsToStrings, getPinnedCertsAsSlice, getMonitorGWOptions, createOutboundRemoteGatewayz, createOutboundAccountsGatewayz, createAccountOutboundGatewayz, createInboundAccountsGatewayz, createInboundAccountGatewayz, ResponseHandler, handleResponse, newExtServiceLatency, newExtImport). Group D: Implement GetScheduledMessages in MsgScheduling; add Seq field to InMsg for out-of-band scheduling sort. Group B (GatewayInterestMode.String) already complete.