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/signserver/dbutils_test.go

@@ -5,6 +5,7 @@ import (
 	"testing"
 	"time"
 
+	"erupe-ce/config"
 	"github.com/DATA-DOG/go-sqlmock"
 	"github.com/jmoiron/sqlx"
 	"go.uber.org/zap"
@@ -301,8 +302,9 @@ func newTestServerWithMock(t *testing.T) (*Server, sqlmock.Sqlmock) {
 	sqlxDB := sqlx.NewDb(db, "sqlmock")
 
 	server := &Server{
-		logger: zap.NewNop(),
-		db:     sqlxDB,
+		logger:      zap.NewNop(),
+		db:          sqlxDB,
+		erupeConfig: &_config.Config{},
 	}
 
 	return server, mock