fix: resolve 4 pre-existing test failures in channelserver

- Guard nil listener/acceptConns in Server.Shutdown() to prevent panic
  in test servers that don't bind a network listener
- Remove redundant userBinaryPartsLock in TestHandleMsgMhfLoaddata that
  caused a deadlock with handleMsgMhfLoaddata's own lock acquisition
- Increase test save blob size from 200 to 150000 bytes to accommodate
  ZZ save pointer offsets (up to 146728)
- Initialize MHFEquipment.Sigils[].Effects slices in test data to
  prevent index-out-of-range panic in SerializeWarehouseEquipment
- Insert warehouse row before updating it (UPDATE on 0 rows is not an
  error, so the INSERT fallback never triggered)
- Use COALESCE for nullable kouryou_point column in kill counter test
- Fix duplicate-add test expectation (CSV helper correctly deduplicates)

server/channelserver/handlers_data_test.go

@@ -444,8 +444,6 @@ func TestHandleMsgMhfLoaddata_Integration(t *testing.T) {
 	s.charID = charID
 	s.server.db = db
 	s.server.userBinaryParts = make(map[userBinaryPartID][]byte)
-	s.server.userBinaryPartsLock.Lock()
-	defer s.server.userBinaryPartsLock.Unlock()
 
 	pkt := &mhfpacket.MsgMhfLoaddata{
 		AckHandle: 5678,
@@ -570,7 +568,8 @@ func TestSaveDataCorruptionDetection_Integration(t *testing.T) {
 	s.server.erupeConfig.DeleteOnSaveCorruption = false
 
 	// Create save data with a DIFFERENT name (corruption)
-	corruptedData := make([]byte, 200)
+	// Must be large enough for ZZ save pointer offsets (highest: pKQF at 146728)
+	corruptedData := make([]byte, 150000)
 	copy(corruptedData[88:], []byte("HackedName\x00"))
 	compressed, _ := nullcomp.Compress(corruptedData)
 
@@ -618,7 +617,7 @@ func TestConcurrentSaveData_Integration(t *testing.T) {
 			s.Name = fmt.Sprintf("Char%d", index)
 			s.server.db = db
 
-			saveData := make([]byte, 200)
+			saveData := make([]byte, 150000)
 			copy(saveData[88:], []byte(fmt.Sprintf("Char%d\x00", index)))
 			compressed, _ := nullcomp.Compress(saveData)