- logger.cpp: use localtime_s on Windows (reversed arg order vs localtime_r)
- process.hpp: drop constexpr on INVALID_PROCESS (INVALID_HANDLE_VALUE is a
reinterpret_cast, not valid in constexpr context)
- world_packets.hpp: push/pop ERROR macro around CharCreateResult enum to avoid
clash with wingdi.h #define ERROR 0
Implement full mail send/receive: SMSG_SHOW_MAILBOX, CMSG_GET_MAIL_LIST,
SMSG_MAIL_LIST_RESULT, CMSG_SEND_MAIL, SMSG_SEND_MAIL_RESULT, mail take
money/item/delete/mark-as-read, and inbox/compose UI windows.
Fix periodic stuttering in Stormwind caused by synchronous per-line disk
flushes in the logger — remove fileStream.flush() and std::endl, downgrade
high-volume per-packet/per-model/per-texture LOG_INFO to LOG_DEBUG.
Online world entry now shows a progress bar during character model,
terrain, and tile streaming. Fixed loading screen crash from calling
ImGui::NewFrame while a frame was already in progress. Log file is
now truncated on each launch instead of appending.