Three critical bugs fixed:
- LOGON_CHALLENGE request: set protocol byte to 0x03 (was 0x00) and
reverse FourCC strings (game/platform/os/locale) to match real client
- Response parsers: remove double-read of opcode byte that shifted all
field reads by one, preventing successful auth with real servers
- LOGON_PROOF response sizes: success=32 bytes, failure=4 bytes to match
TrinityCore/AzerothCore format
Also adds missing auth result codes (0x13-0x20, 0xFF) including
IGR_WITHOUT_BNET (0x17) which Warmane was returning.