Add XML doc comments to public properties across EventTypes, Connz, Varz,
NatsOptions, StreamConfig, IStreamStore, FileStore, MqttListener,
MqttSessionStore, MessageTraceContext, and JetStreamApiResponse. Fix flaky
tests by increasing timing margins (ResponseTracker expiry 1ms→50ms,
sleep 50ms→200ms) and document known flaky test patterns in tests.md.
Move 43 Raft consensus test files (8 root-level + 35 in Raft/ subfolder)
from NATS.Server.Tests into a dedicated NATS.Server.Raft.Tests project.
Update namespaces, add InternalsVisibleTo, and fix timing/exception
handling issues in moved test files.
