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/config/config.go

@@ -11,6 +11,7 @@ import (
 	"github.com/mitchellh/mapstructure"
 	"github.com/spf13/pflag"
 	"github.com/spf13/viper"
+	"go.uber.org/zap"
 	"gopkg.in/yaml.v3"
 
 	appErrors "nex/backend/pkg/errors"
@@ -33,12 +34,12 @@ type ServerConfig struct {
 // DatabaseConfig 数据库配置
 type DatabaseConfig struct {
 	Driver          string        `yaml:"driver" mapstructure:"driver" validate:"required,oneof=sqlite mysql"`
-	Path            string        `yaml:"path" mapstructure:"path" validate:"required_if=driver sqlite"`
-	Host            string        `yaml:"host" mapstructure:"host" validate:"required_if=driver mysql"`
-	Port            int           `yaml:"port" mapstructure:"port" validate:"required_if=driver mysql,min=1,max=65535"`
-	User            string        `yaml:"user" mapstructure:"user" validate:"required_if=driver mysql"`
+	Path            string        `yaml:"path" mapstructure:"path" validate:"required_if=Driver sqlite"`
+	Host            string        `yaml:"host" mapstructure:"host" validate:"required_if=Driver mysql"`
+	Port            int           `yaml:"port" mapstructure:"port" validate:"required_if=Driver mysql,min=1,max=65535"`
+	User            string        `yaml:"user" mapstructure:"user" validate:"required_if=Driver mysql"`
 	Password        string        `yaml:"password" mapstructure:"password"`
-	DBName          string        `yaml:"dbname" mapstructure:"dbname" validate:"required_if=driver mysql"`
+	DBName          string        `yaml:"dbname" mapstructure:"dbname" validate:"required_if=Driver mysql"`
 	MaxIdleConns    int           `yaml:"max_idle_conns" mapstructure:"max_idle_conns" validate:"required,min=1"`
 	MaxOpenConns    int           `yaml:"max_open_conns" mapstructure:"max_open_conns" validate:"required,min=1"`
 	ConnMaxLifetime time.Duration `yaml:"conn_max_lifetime" mapstructure:"conn_max_lifetime" validate:"required"`
@@ -311,22 +312,24 @@ func (c *Config) Validate() error {
 }
 
 // PrintSummary 打印配置摘要
-func (c *Config) PrintSummary() {
-	fmt.Println("\nAI Gateway 启动配置")
-	fmt.Println("==================")
-	fmt.Printf("服务器端口:     %d\n", c.Server.Port)
+func (c *Config) PrintSummary(logger *zap.Logger) {
+	logger.Info("AI Gateway 启动配置",
+		zap.Int("server_port", c.Server.Port),
+		zap.String("database_driver", c.Database.Driver),
+		zap.String("log_level", c.Log.Level),
+	)
+
 	if c.Database.Driver == "mysql" {
-		fmt.Printf("数据库类型:     mysql\n")
-		fmt.Printf("数据库地址:     %s:%d/%s\n", c.Database.Host, c.Database.Port, c.Database.DBName)
+		logger.Info("数据库配置",
+			zap.String("driver", "mysql"),
+			zap.String("host", c.Database.Host),
+			zap.Int("port", c.Database.Port),
+			zap.String("database", c.Database.DBName),
+		)
 	} else {
-		fmt.Printf("数据库类型:     sqlite\n")
-		fmt.Printf("数据库路径:     %s\n", c.Database.Path)
+		logger.Info("数据库配置",
+			zap.String("driver", "sqlite"),
+			zap.String("path", c.Database.Path),
+		)
 	}
-	fmt.Printf("日志级别:       %s\n", c.Log.Level)
-	fmt.Println("\n配置来源:")
-	configPath, _ := GetConfigPath()
-	fmt.Printf("  配置文件:     %s\n", configPath)
-	fmt.Println("  环境变量:     待统计")
-	fmt.Println("  CLI 参数:     待统计")
-	fmt.Println()
 }

backend/internal/config/config_test.go

@@ -8,6 +8,7 @@ import (
 
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
+	"go.uber.org/zap"
 	"gopkg.in/yaml.v3"
 )
 
@@ -171,7 +172,9 @@ func TestConfig_Validate(t *testing.T) {
 			err := cfg.Validate()
 			if tt.wantErr {
 				assert.Error(t, err)
-				assert.Contains(t, err.Error(), tt.errMsg)
+				if err != nil {
+					assert.Contains(t, err.Error(), tt.errMsg)
+				}
 			} else {
 				assert.NoError(t, err)
 			}
@@ -302,7 +305,7 @@ func TestPrintSummary(t *testing.T) {
 	t.Run("SQLite模式摘要", func(t *testing.T) {
 		cfg := DefaultConfig()
 		assert.NotPanics(t, func() {
-			cfg.PrintSummary()
+			cfg.PrintSummary(zap.NewNop())
 		})
 	})
 	t.Run("MySQL模式摘要", func(t *testing.T) {
@@ -313,7 +316,7 @@ func TestPrintSummary(t *testing.T) {
 		cfg.Database.User = "nex"
 		cfg.Database.DBName = "nex"
 		assert.NotPanics(t, func() {
-			cfg.PrintSummary()
+			cfg.PrintSummary(zap.NewNop())
 		})
 	})
 }