SMSG_ACHIEVEMENT_EARNED carries a PACKED player GUID in WotLK, not a full uint64.
Reading it as uint64 swallowed 4 bytes of the achievement id, so the message showed
a raw GUID (0x...8951D07) and a garbage id (442831322). Decode the packed GUID so
the name resolves and the achievement id is correct.
SMSG_GUILD_EVENT SIGNED_ON/OFF now only announces a genuine online<->offline
transition (tracked via the roster's cached online flag), matching the real client
and dropping the login-time flood of 'has come online' guild-chat spam.