refactor(config): rename package _config to config with cfg alias

The config package used `package _config` with a leading underscore,
which is unconventional in Go. Rename to `package config` (matching the
directory name) and use `cfg` as the standard import alias across all
93 importing files.

server/channelserver/handlers_quest_test.go

@@ -4,7 +4,7 @@ import (
 	"bytes"
 	"encoding/binary"
 	"erupe-ce/common/byteframe"
-	_config "erupe-ce/config"
+	cfg "erupe-ce/config"
 	"erupe-ce/network/mhfpacket"
 	"os"
 	"path/filepath"
@@ -62,7 +62,7 @@ func TestBackportQuestBasic(t *testing.T) {
 				}
 			}()
 
-			result := BackportQuest(data, _config.ZZ)
+			result := BackportQuest(data, cfg.ZZ)
 			if result != nil && !tc.verify(result) {
 				t.Errorf("BackportQuest verification failed for result: %d bytes", len(result))
 			}
@@ -686,7 +686,7 @@ func BenchmarkBackportQuest(b *testing.B) {
 	binary.LittleEndian.PutUint32(data[0:4], 100)
 
 	for i := 0; i < b.N; i++ {
-		_ = BackportQuest(data, _config.ZZ)
+		_ = BackportQuest(data, cfg.ZZ)
 	}
 }