refactor(config): eliminate ErupeConfig global variable

Replace the mutable global `_config.ErupeConfig` with dependency
injection across 79 files. Config is now threaded through existing
paths: `ClientContext.RealClientMode` for packet encoding, `s.server.
erupeConfig` for channel handlers, and explicit parameters for utility
functions. This removes hidden coupling, enables test parallelism
without global save/restore, and prevents low-level packages from
reaching up to the config layer.

Key changes:
- Enrich ClientContext with RealClientMode for packet files
- Add mode parameter to CryptConn, mhfitem, mhfcourse functions
- Convert handlers_commands init() to lazy sync.Once initialization
- Delete global var, init(), and helper functions from config.go
- Update all tests to pass config explicitly

server/channelserver/handlers_event.go

@@ -69,7 +69,7 @@ func handleMsgMhfGetWeeklySchedule(s *Session, p mhfpacket.MHFPacket) {
 		err := s.server.db.QueryRowx(`SELECT start_time, featured FROM feature_weapon WHERE start_time=$1`, t).StructScan(&temp)
 		if err != nil || temp.StartTime.IsZero() {
 			weapons := token.RNG.Intn(s.server.erupeConfig.GameplayOptions.MaxFeatureWeapons-s.server.erupeConfig.GameplayOptions.MinFeatureWeapons+1) + s.server.erupeConfig.GameplayOptions.MinFeatureWeapons
-			temp = generateFeatureWeapons(weapons)
+			temp = generateFeatureWeapons(weapons, s.server.erupeConfig.RealClientMode)
 			temp.StartTime = t
 			if _, err := s.server.db.Exec(`INSERT INTO feature_weapon VALUES ($1, $2)`, temp.StartTime, temp.ActiveFeatures); err != nil {
 				s.logger.Error("Failed to insert feature weapon", zap.Error(err))
@@ -89,15 +89,15 @@ func handleMsgMhfGetWeeklySchedule(s *Session, p mhfpacket.MHFPacket) {
 	doAckBufSucceed(s, pkt.AckHandle, bf.Data())
 }
 
-func generateFeatureWeapons(count int) activeFeature {
+func generateFeatureWeapons(count int, mode _config.Mode) activeFeature {
 	_max := 14
-	if _config.ErupeConfig.RealClientMode < _config.ZZ {
+	if mode < _config.ZZ {
 		_max = 13
 	}
-	if _config.ErupeConfig.RealClientMode < _config.G10 {
+	if mode < _config.G10 {
 		_max = 12
 	}
-	if _config.ErupeConfig.RealClientMode < _config.GG {
+	if mode < _config.GG {
 		_max = 11
 	}
 	if count > _max {