Add quest opcodes, fix gossip select packet, and NPC combat animations

Fix CMSG_GOSSIP_SELECT_OPTION missing menuId field (was causing
ByteBufferException). Add 12 quest opcodes and clickable quest items in
gossip dialog. NPC attack/death animation callbacks now work for both
single-player and server-spawned creatures, and SMSG_ATTACKERSTATEUPDATE
triggers NPC swing animations.

include/game/game_handler.hpp

@@ -321,6 +321,7 @@ public:
     // NPC Gossip
     void interactWithNpc(uint64_t guid);
     void selectGossipOption(uint32_t optionId);
+    void selectGossipQuest(uint32_t questId);
     void closeGossip();
     bool isGossipWindowOpen() const { return gossipWindowOpen; }
     const GossipMessageData& getCurrentGossip() const { return currentGossip; }