The gossip questIcon field is an integer enum (2=available, 4=incomplete,
5=ready-to-turn-in), not a bitmask. Using (questIcon & 0x04) caused icon=4
(in-progress quests) to be treated as completable, so the client sent
CMSG_QUESTGIVER_REQUEST_REWARD for incomplete quests. The server rejected
these silently and re-sent SMSG_GOSSIP_MESSAGE, causing an infinite loop.
Fix: use exact equality (questIcon == 5 for completable, == 4 for incomplete).
Also register SMSG_CANCEL_AUTO_REPEAT (0x06B) to suppress the unhandled
opcode warning logged on every login.