refactor(mhfpacket): rename 15 Unk fields with identified meanings

Replace unknown field names with descriptive names based on handler
logic analysis, switch dispatch patterns, DB query context, and
inline comments:

- ObjectHandleID, IsQuest, ItemIDCount, MaxCount, TokenLength,
  FormatVersion, LogoutType (high confidence from comments/constants)
- QueryType, DataType, MissionIndex, CheckOnly, RequestType,
  ExchangeType, TournamentID (confirmed by handler switch/if usage)

Also fix MsgSysLogout.Build calling ReadUint8 instead of WriteUint8.

network/mhfpacket/msg_sys_update_object_binary.go

@@ -8,8 +8,8 @@ import (
 
 // MsgSysUpdateObjectBinary represents the MSG_SYS_UPDATE_OBJECT_BINARY
 type MsgSysUpdateObjectBinary struct {
-	Unk0 uint32 // Object handle ID
-	Unk1 uint32
+	ObjectHandleID uint32
+	Unk1           uint32
 }
 
 // Opcode returns the ID associated with this packet type.
@@ -19,14 +19,14 @@ func (m *MsgSysUpdateObjectBinary) Opcode() network.PacketID {
 
 // Parse parses the packet from binary
 func (m *MsgSysUpdateObjectBinary) Parse(bf *byteframe.ByteFrame, ctx *clientctx.ClientContext) error {
-	m.Unk0 = bf.ReadUint32()
+	m.ObjectHandleID = bf.ReadUint32()
 	m.Unk1 = bf.ReadUint32()
 	return nil
 }
 
 // Build builds a binary packet from the current data.
 func (m *MsgSysUpdateObjectBinary) Build(bf *byteframe.ByteFrame, ctx *clientctx.ClientContext) error {
-	bf.WriteUint32(m.Unk0)
+	bf.WriteUint32(m.ObjectHandleID)
 	bf.WriteUint32(m.Unk1)
 	return nil
 }