1630f6f163
nats.go refuses to connect with an nkey to a server that does not advertise
nkey auth, so the connection cannot blindly always present one. New keeps the
legacy plain connection; NewWithOptions(Options{UseNkey:true}) presents the
peer's identity-derived nkey. NewWithOptions is the single place the data-plane
connection is built, so every peer gets identical behavior from the same
Options (TLS fields arrive in phase 0001d).
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>