refactor: 添加 logger 模块并优化客户端实例清理逻辑

- 新增 logger 模块，统一使用 zap.SugaredLogger
- 将 config_api.go 中的 fmt.Printf 改为 logger.SugaredLogger.Errorf
- 客户端实例清理逻辑改为定时任务（每分钟执行）
- 清理条件改为 last_ping_at 超过 5 分钟

server/internal/handler/config_api.go

@@ -1,8 +1,8 @@
 package handler
 
 import (
-	"fmt"
 	"kenaito-conf/server/internal/dao"
+	"kenaito-conf/server/internal/logger"
 	"kenaito-conf/server/internal/model"
 	"kenaito-conf/server/internal/service"
 	"net/http"
@@ -242,14 +242,11 @@ func (h *ConfigApiHandler) recordClientInstances(ip string, configIds []int, app
 			}
 			_, err := dao.Engine.Insert(&instance)
 			if err != nil {
-				fmt.Printf("[recordClientInstances] insert error: %v\n", err)
+				logger.SugaredLogger.Errorf("[recordClientInstances] insert error: %v", err)
 				continue
 			}
 		}
 	}
-	// cleanup records older than 5 minutes
-	fiveMinutesAgo := now.Add(-5 * time.Minute)
-	dao.Engine.Where("last_ping_at < ?", fiveMinutesAgo).Delete(&model.ClientInstance{})
 }
 
 // func (h *ConfigApiHandler) Ping(c *gin.Context) {

server/internal/logger/index.go

@@ -0,0 +1,57 @@
+package logger
+
+import (
+	"os"
+	"time"
+
+	"go.uber.org/zap"
+	"go.uber.org/zap/zapcore"
+	"gopkg.in/natefinch/lumberjack.v2"
+)
+
+var globalLogger *zap.Logger
+
+// SugaredLogger 全局 SugaredLogger，任意位置可直接使用
+var SugaredLogger *zap.SugaredLogger
+
+// 初始化全局日志（控制台 + application.log 轮转文件）
+func init() {
+	encoderConfig := zapcore.EncoderConfig{
+		TimeKey:       "time",
+		LevelKey:      "level",
+		NameKey:       "logger",
+		CallerKey:     "caller",
+		MessageKey:    "msg",
+		StacktraceKey: "stack",
+		LineEnding:    zapcore.DefaultLineEnding,
+		EncodeLevel:   zapcore.CapitalColorLevelEncoder,
+		EncodeTime: func(t time.Time, enc zapcore.PrimitiveArrayEncoder) {
+			enc.AppendString(t.Format("2006-01-02 15:04:05"))
+		},
+		EncodeDuration: zapcore.StringDurationEncoder,
+		EncodeCaller:   zapcore.ShortCallerEncoder,
+	}
+
+	// 日志轮转配置
+	lumberjackLogger := &lumberjack.Logger{
+		Filename:   "application.log",
+		MaxSize:    100,  // 每个日志文件最大 100MB
+		MaxBackups: 5,    // 最多保留 5 个旧日志文件
+		MaxAge:     30,   // 日志文件最多保留 30 天
+		Compress:   true, // 压缩旧日志
+	}
+
+	// 同时输出到控制台和文件
+	consoleEncoder := zapcore.NewConsoleEncoder(encoderConfig)
+	consoleWriter := zapcore.AddSync(os.Stdout)
+	fileWriter := zapcore.AddSync(lumberjackLogger)
+
+	core := zapcore.NewTee(
+		zapcore.NewCore(consoleEncoder, consoleWriter, zap.InfoLevel),
+		zapcore.NewCore(consoleEncoder, fileWriter, zap.InfoLevel),
+	)
+
+	globalLogger = zap.New(core, zap.AddCaller(), zap.AddStacktrace(zap.ErrorLevel))
+	SugaredLogger = globalLogger.Sugar()
+	zap.ReplaceGlobals(globalLogger)
+}