test: increase code coverage from 45.1% to 48.3%

Add unit tests across multiple packages:
- byteframe: SetBE/SetLE byte order switching
- config: Mode.String() for all safe version ranges
- mhfpacket: 28 Parse methods, 5 Build methods, empty packet builds,
  variable-length packets, NOT IMPLEMENTED error paths, UpdateWarehouse
- network: PacketID.String() for known IDs, out-of-range, and all valid
- channelserver: handleMsgMhfGetPaperData (6 switch cases), grpToGR
  (11 input values), gacha handlers, TimeGameAbsolute, equipSkinHistSize
  (4 config branches), guild mission handlers, dumpSaveData disabled path
- entranceserver: makeHeader with various inputs

server/channelserver/handlers_coverage5_test.go

@@ -0,0 +1,202 @@
+package channelserver
+
+import (
+	"testing"
+
+	_config "erupe-ce/config"
+	"erupe-ce/network/mhfpacket"
+)
+
+// =============================================================================
+// equipSkinHistSize: pure function, tests all 3 config branches
+// =============================================================================
+
+func TestEquipSkinHistSize_Default(t *testing.T) {
+	orig := _config.ErupeConfig.RealClientMode
+	defer func() { _config.ErupeConfig.RealClientMode = orig }()
+
+	_config.ErupeConfig.RealClientMode = _config.ZZ
+	got := equipSkinHistSize()
+	if got != 3200 {
+		t.Errorf("equipSkinHistSize() with ZZ = %d, want 3200", got)
+	}
+}
+
+func TestEquipSkinHistSize_Z2(t *testing.T) {
+	orig := _config.ErupeConfig.RealClientMode
+	defer func() { _config.ErupeConfig.RealClientMode = orig }()
+
+	_config.ErupeConfig.RealClientMode = _config.Z2
+	got := equipSkinHistSize()
+	if got != 2560 {
+		t.Errorf("equipSkinHistSize() with Z2 = %d, want 2560", got)
+	}
+}
+
+func TestEquipSkinHistSize_Z1(t *testing.T) {
+	orig := _config.ErupeConfig.RealClientMode
+	defer func() { _config.ErupeConfig.RealClientMode = orig }()
+
+	_config.ErupeConfig.RealClientMode = _config.Z1
+	got := equipSkinHistSize()
+	if got != 1280 {
+		t.Errorf("equipSkinHistSize() with Z1 = %d, want 1280", got)
+	}
+}
+
+func TestEquipSkinHistSize_OlderMode(t *testing.T) {
+	orig := _config.ErupeConfig.RealClientMode
+	defer func() { _config.ErupeConfig.RealClientMode = orig }()
+
+	_config.ErupeConfig.RealClientMode = _config.G1
+	got := equipSkinHistSize()
+	if got != 1280 {
+		t.Errorf("equipSkinHistSize() with G1 = %d, want 1280", got)
+	}
+}
+
+// =============================================================================
+// DB-free guild handlers: simple ack stubs
+// =============================================================================
+
+func TestHandleMsgMhfAddGuildMissionCount(t *testing.T) {
+	server := createMockServer()
+	session := createMockSession(1, server)
+
+	handleMsgMhfAddGuildMissionCount(session, &mhfpacket.MsgMhfAddGuildMissionCount{
+		AckHandle: 1,
+	})
+
+	select {
+	case p := <-session.sendPackets:
+		if len(p.data) == 0 {
+			t.Error("response should have data")
+		}
+	default:
+		t.Error("no response queued")
+	}
+}
+
+func TestHandleMsgMhfSetGuildMissionTarget(t *testing.T) {
+	server := createMockServer()
+	session := createMockSession(1, server)
+
+	handleMsgMhfSetGuildMissionTarget(session, &mhfpacket.MsgMhfSetGuildMissionTarget{
+		AckHandle: 1,
+	})
+
+	select {
+	case p := <-session.sendPackets:
+		if len(p.data) == 0 {
+			t.Error("response should have data")
+		}
+	default:
+		t.Error("no response queued")
+	}
+}
+
+func TestHandleMsgMhfCancelGuildMissionTarget(t *testing.T) {
+	server := createMockServer()
+	session := createMockSession(1, server)
+
+	handleMsgMhfCancelGuildMissionTarget(session, &mhfpacket.MsgMhfCancelGuildMissionTarget{
+		AckHandle: 1,
+	})
+
+	select {
+	case p := <-session.sendPackets:
+		if len(p.data) == 0 {
+			t.Error("response should have data")
+		}
+	default:
+		t.Error("no response queued")
+	}
+}
+
+func TestHandleMsgMhfGetGuildMissionRecord(t *testing.T) {
+	server := createMockServer()
+	session := createMockSession(1, server)
+
+	handleMsgMhfGetGuildMissionRecord(session, &mhfpacket.MsgMhfGetGuildMissionRecord{
+		AckHandle: 1,
+	})
+
+	select {
+	case p := <-session.sendPackets:
+		if len(p.data) == 0 {
+			t.Error("response should have data")
+		}
+	default:
+		t.Error("no response queued")
+	}
+}
+
+func TestHandleMsgMhfAcquireGuildTresureSouvenir(t *testing.T) {
+	server := createMockServer()
+	session := createMockSession(1, server)
+
+	handleMsgMhfAcquireGuildTresureSouvenir(session, &mhfpacket.MsgMhfAcquireGuildTresureSouvenir{
+		AckHandle: 1,
+	})
+
+	select {
+	case p := <-session.sendPackets:
+		if len(p.data) == 0 {
+			t.Error("response should have data")
+		}
+	default:
+		t.Error("no response queued")
+	}
+}
+
+func TestHandleMsgMhfGetUdGuildMapInfo(t *testing.T) {
+	server := createMockServer()
+	session := createMockSession(1, server)
+
+	handleMsgMhfGetUdGuildMapInfo(session, &mhfpacket.MsgMhfGetUdGuildMapInfo{
+		AckHandle: 1,
+	})
+
+	select {
+	case p := <-session.sendPackets:
+		if len(p.data) == 0 {
+			t.Error("response should have data")
+		}
+	default:
+		t.Error("no response queued")
+	}
+}
+
+// =============================================================================
+// DB-free guild mission list handler (large static data)
+// =============================================================================
+
+func TestHandleMsgMhfGetGuildMissionList(t *testing.T) {
+	server := createMockServer()
+	session := createMockSession(1, server)
+
+	handleMsgMhfGetGuildMissionList(session, &mhfpacket.MsgMhfGetGuildMissionList{
+		AckHandle: 1,
+	})
+
+	select {
+	case p := <-session.sendPackets:
+		if len(p.data) == 0 {
+			t.Error("response should have data")
+		}
+	default:
+		t.Error("no response queued")
+	}
+}
+
+// handleMsgMhfEnumerateUnionItem requires DB (calls userGetItems)
+
+// handleMsgMhfRegistSpabiTime, handleMsgMhfKickExportForce, handleMsgMhfUseUdShopCoin
+// are tested in handlers_misc_test.go
+
+// handleMsgMhfGetUdShopCoin and handleMsgMhfGetLobbyCrowd are tested in handlers_misc_test.go
+
+// handleMsgMhfEnumerateGuacot requires DB (calls getGoocooData)
+
+// handleMsgMhfPostRyoudama is tested in handlers_caravan_test.go
+// handleMsgMhfResetTitle is tested in handlers_coverage2_test.go