refactor: 后端日志系统重构

- 新增模块化日志器（pkg/logger/module.go）
- 新增 GORM 日志适配器
- 统一日志入口，移除所有 zap.L() 全局 logger 调用
- 字段标准化
- 启动阶段使用结构化日志
- 更新所有相关测试

backend/internal/handler/middleware/logging.go

@@ -5,9 +5,10 @@ import (
 
 	"github.com/gin-gonic/gin"
 	"go.uber.org/zap"
+
+	pkglogger "nex/backend/pkg/logger"
 )
 
-// Logging 日志中间件
 func Logging(logger *zap.Logger) gin.HandlerFunc {
 	return func(c *gin.Context) {
 		start := time.Now()
@@ -15,12 +16,17 @@ func Logging(logger *zap.Logger) gin.HandlerFunc {
 		query := c.Request.URL.RawQuery
 
 		requestID, _ := c.Get(RequestIDKey)
+		var requestIDStr string
+		if id, ok := requestID.(string); ok {
+			requestIDStr = id
+		}
+		
 		logger.Info("请求开始",
-			zap.String("method", c.Request.Method),
-			zap.String("path", path),
-			zap.String("query", query),
-			zap.String("client_ip", c.ClientIP()),
-			zap.Any("request_id", requestID),
+			pkglogger.Method(c.Request.Method),
+			pkglogger.Path(path),
+			pkglogger.Query(query),
+			pkglogger.ClientIP(c.ClientIP()),
+			pkglogger.RequestID(requestIDStr),
 		)
 
 		c.Next()
@@ -29,12 +35,12 @@ func Logging(logger *zap.Logger) gin.HandlerFunc {
 		statusCode := c.Writer.Status()
 
 		logger.Info("请求结束",
-			zap.Int("status", statusCode),
-			zap.String("method", c.Request.Method),
-			zap.String("path", path),
-			zap.Duration("latency", latency),
-			zap.Int("body_size", c.Writer.Size()),
-			zap.Any("request_id", requestID),
+			pkglogger.StatusCode(statusCode),
+			pkglogger.Method(c.Request.Method),
+			pkglogger.Path(path),
+			pkglogger.Latency(latency),
+			pkglogger.BodySize(c.Writer.Size()),
+			pkglogger.RequestID(requestIDStr),
 		)
 	}
 }