fix: mail money uint64, other-player cape textures, zone toast dedup, TCP_NODELAY

Mail: change money/COD fields from uint32 to uint64 in CMSG_SEND_MAIL and
SMSG_MAIL_LIST_RESULT for WotLK 3.3.5a. Classic keeps uint32 on the wire.
Fixes money truncation and packet misalignment causing mail failures.

Other-player capes: add cape texture loading to setOnlinePlayerEquipment().
The cape geoset was enabled but no texture was loaded, leaving capes blank.
Now mirrors the local-player path: looks up ItemDisplayInfo.dbc, finds cape
texture candidates, applies via setGroupTextureOverride/setTextureSlotOverride.

Zone toasts: suppress duplicate zone toast when the zone text overlay is
already showing the same zone name. Fixes double "Entering: Stormwind City".

Network: enable TCP_NODELAY on both auth and world sockets after connect(),
disabling Nagle's algorithm to eliminate up to 200ms buffering delay on
small packets (movement, spell casts, chat).

Rendering: track material and bone descriptor sets in M2 renderer to skip
redundant vkCmdBindDescriptorSets calls between batches sharing same textures.

include/network/net_platform.hpp

@@ -22,6 +22,7 @@
   #include <netinet/in.h>
   #include <arpa/inet.h>
   #include <netdb.h>
+  #include <netinet/tcp.h>
   #include <unistd.h>
   #include <fcntl.h>
   #include <cerrno>