ai优化，删除未使用代码，提取重复代码。

config/config.go

@@ -2,8 +2,6 @@ package config
 
 import (
 	"log/slog"
-	"os"
-	"strconv"
 
 	"github.com/fsnotify/fsnotify"
 	"github.com/spf13/viper"
@@ -82,18 +80,13 @@ func setDefaults() {
 
 // parseConfig 解析配置到结构体
 func parseConfig() *Config {
-	port := viper.GetInt("server.port")
-	if port == 0 {
-		port, _ = strconv.Atoi(getEnv("SERVER_PORT", "8080"))
-	}
-
 	return &Config{
 		Database: DatabaseConfig{
 			Driver: viper.GetString("database.driver"),
 			DSN:    viper.GetString("database.dsn"),
 		},
 		Server: ServerConfig{
-			Port: port,
+			Port: viper.GetInt("server.port"),
 			Mode: viper.GetString("server.mode"),
 		},
 		App: AppConfig{
@@ -124,11 +117,3 @@ func watchConfig() {
 func GetGlobalConfig() *Config {
 	return globalConfig
 }
-
-// getEnv 获取环境变量
-func getEnv(key, defaultValue string) string {
-	if value := os.Getenv(key); value != "" {
-		return value
-	}
-	return defaultValue
-}