fix(parsing): correct UPDATE_OBJECT PackedGuid, cape textures, and missing asset guards

- Fix MOVEMENT update type to use readPackedGuid() instead of readUInt64() (WotLK 3.3.5a)
- Add desync diagnostic logging to UPDATE_OBJECT parser for future debugging
- Register MSG_MOVE_SET_COLLISION_HGT (0x518) as skip handler
- Fix cape texture lookup to only try .blp extension variants (4 files)
- Add fileExists() guards for underwear textures referencing missing BLP files (4 files)
- Add spell visual impact→cast M2 path fallback
- Skip WMO doodad instance creation when model load fails
- Demote spell caster position warning to debug level

src/game/game_handler_packets.cpp

@@ -2523,6 +2523,8 @@ void GameHandler::registerOpcodeHandlers() {
     };
     // GM ticket status (new/updated); no ticket UI yet
     registerSkipHandler(Opcode::SMSG_GM_TICKET_STATUS_UPDATE);
+    // Broadcast of another player's collision height change — cosmetic only.
+    registerSkipHandler(Opcode::MSG_MOVE_SET_COLLISION_HGT);
     // Client uses this outbound; treat inbound variant as no-op for robustness.
     registerSkipHandler(Opcode::MSG_MOVE_WORLDPORT_ACK);
     // Observed custom server packet (8 bytes). Safe-consume for now.