chore: bump NosCore.Packets to 19.0.0 (#13) Picks up NsTeST leading-blank field (fixes FormatException on real login traffic with the vanosilla `NsTeST <region>` double-space format) and SuPacketHitMode widened to sbyte with the full -2..7 value set. Co-authored-by: Claude Opus 4.7 (1M context) <noreply@anthropic.com>