Add 27 new opcodes, packet builders/parsers, handler methods, inventory
extension with 28 bank slots + 7 bank bags, and UI windows for personal
bank, guild bank (6 tabs x 98 slots), and auction house (browse/sell/bid).
Fix Classic gossip parser to omit boxMoney/boxText fields not present in
Vanilla protocol, fix gossip icon labels with text-based NPC type detection,
and add Turtle WoW opcode mappings for bank and auction interactions.
Vanilla CMSG_CAST_SPELL target mask is uint16 (not uint32 like WotLK),
the extra 2 bytes were corrupting packets. Also implement full bag
content tracking: extract container slot GUIDs from CONTAINER update
objects, set proper bag sizes, and populate bag items in inventory
rebuild.
