全局重命名：kefu_sys / kefu-sys 改为 kefu_cloud / kefu-cloud

- Go module 与全部 import 路径
- 数据库默认库名、Docker 服务/卷命名与部署文档

server/internal/handler/security_integration_test.go

@@ -15,11 +15,11 @@ import (
 	"golang.org/x/crypto/bcrypt"
 	"gorm.io/driver/sqlite"
 	"gorm.io/gorm"
-	"kefu-sys/server/internal/config"
-	"kefu-sys/server/internal/handler"
-	"kefu-sys/server/internal/middleware"
-	"kefu-sys/server/internal/model"
-	"kefu-sys/server/internal/storage"
+	"kefu-cloud/server/internal/config"
+	"kefu-cloud/server/internal/handler"
+	"kefu-cloud/server/internal/middleware"
+	"kefu-cloud/server/internal/model"
+	"kefu-cloud/server/internal/storage"
 )
 
 func setupRouter(t *testing.T) *gin.Engine {