refactor: world packets as structs

WorldPackets now holds what a client sends a world server, one struct per
packet with Serialize/Deserialize: Validation, CharacterListRequest,
CharacterCreateRequest, CharacterLoginRequest, GameMessage,
CharacterDeleteRequest, CharacterRenameRequest, LevelLoadComplete,
PositionUpdate, MailPacket, RoutePacket, StringCheck, GeneralChatMessage,
HandleFunness, UIHelpTop5. WorldServer's switch became a dispatch map of
handlers (each overrides Handle in WorldServer.cpp, logic unchanged:
dashboard hooks, LoadPlayer, chat logging, migration checks, message
inspector capture all still run); a packet that does not deserialize is
logged and dropped. UserManager's create/delete/rename take the structs.

The answers are ClientPackets (the CLIENT service): LoadStaticZone,
CharacterListResponse, CharacterCreateResponse, CharacterRenameResponse,
DeleteCharacterResponse, TransferToWorld, ServerStates, CreateCharacter,
ChatModerationString, MakeGMResponse, HTTPMonitorInfoResponse and
DebugOutput, built at the call sites (world server, UserManager, slash
commands, dashboard actions, components, migration). The world -> chat
forward of a routed packet is ChatPackets::RoutedFromClient. All
WorldPackets::Send* functions, HTTPMonitorInfo and the ClientPackets parse
functions are gone. The architecture doc now states the file rule: a
packet lives in the file of the ServiceType in its header.

No wire change. Verified against frozen verbatim copies of the old code
(tests/dGameTests/dNetTests/Legacy/WorldPacketsLegacy.h): every response
is sent through the old function and the struct over grids of inputs
(all enum values, strings of every length class, IDs, >64 moderation
segments, big XML) and must match byte for byte; every request is read
by the old code and the struct and must give the same values; plus
golden bytes, round trips, truncation checks and a field width mutation
that made the tests fail. Only differences: malformed requests are
dropped instead of handled with partial values, and LevelLoadComplete now
reads the zone ID the client sends after it (lu_packets and captures show
the 1.10.64 client always sends it; DLU ignored it).

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

dNet/ChatPackets.cpp

@@ -150,3 +150,15 @@ void ChatPackets::SendRoutedMsg(const LUBitStream& msg, const LWOOBJID targetID,
 	msg.WritePacket(bitStream);
 	Game::server->Send(bitStream, sysAddr, sysAddr == UNASSIGNED_SYSTEM_ADDRESS);
 }
+
+void ChatPackets::RoutedFromClient::Serialize(RakNet::BitStream& bitStream) const {
+	bitStream.Write(senderID);
+	for (const auto byte : data) bitStream.Write(byte);
+}
+
+bool ChatPackets::RoutedFromClient::Deserialize(RakNet::BitStream& bitStream) {
+	VALIDATE_READ(bitStream.Read(senderID));
+	data.resize(BITS_TO_BYTES(bitStream.GetNumberOfUnreadBits()));
+	if (!data.empty()) VALIDATE_READ(bitStream.ReadBits(data.data(), BYTES_TO_BITS(data.size()), true));
+	return true;
+}