refactor(channelserver): migrate inline queries to helpers and define named constants

Migrate 6 character data handlers to use the existing loadCharacterData
and saveCharacterData helpers, eliminating duplicate inline SQL:
- LoadFavoriteQuest, SaveFavoriteQuest, LoadDecoMyset, LoadMezfesData,
  LoadHunterNavi, GetEquipSkinHist

Define named constants replacing magic numbers across handlers:
- Achievement trophy tiers, broadcast/message types, diva phase
  durations, RP accrual rates, kill log layout, semaphore bases,
  quest stage/loading screen IDs

Update anti-patterns doc with accurate line counts, evidence-based
softlock analysis, and revised refactoring priorities.

server/channelserver/handlers_mercenary.go

@@ -47,13 +47,7 @@ func handleMsgMhfLoadHunterNavi(s *Session, p mhfpacket.MHFPacket) {
 	if s.server.erupeConfig.RealClientMode <= _config.G7 {
 		naviLength = 280
 	}
-	var data []byte
-	err := s.server.db.QueryRow("SELECT hunternavi FROM characters WHERE id = $1", s.charID).Scan(&data)
-	if len(data) == 0 {
-		s.logger.Error("Failed to load hunternavi", zap.Error(err))
-		data = make([]byte, naviLength)
-	}
-	doAckBufSucceed(s, pkt.AckHandle, data)
+	loadCharacterData(s, pkt.AckHandle, "hunternavi", make([]byte, naviLength))
 }
 
 func handleMsgMhfSaveHunterNavi(s *Session, p mhfpacket.MHFPacket) {