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

network/mhfpacket/msg_opcode_coverage_test.go

@@ -4,6 +4,7 @@ import (
 	"testing"
 
 	"erupe-ce/common/byteframe"
+	_config "erupe-ce/config"
 	"erupe-ce/network/clientctx"
 )
 
@@ -245,7 +246,7 @@ func TestBuildCoverage_NotImplemented(t *testing.T) {
 		{"MsgSysReserve1AF", &MsgSysReserve1AF{}},
 	}
 
-	ctx := &clientctx.ClientContext{}
+	ctx := &clientctx.ClientContext{RealClientMode: _config.ZZ}
 	bf := byteframe.NewByteFrame()
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {
@@ -282,7 +283,7 @@ func TestParseCoverage_NotImplemented(t *testing.T) {
 		{"MsgMhfUpdateGuild", &MsgMhfUpdateGuild{}},
 	}
 
-	ctx := &clientctx.ClientContext{}
+	ctx := &clientctx.ClientContext{RealClientMode: _config.ZZ}
 	bf := byteframe.NewByteFrame()
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {