fix: 修复地理位置GBK编码问题

utils/location.go

@@ -8,6 +8,9 @@ import (
 	"math/rand"
 	"net/http"
 	"time"
+
+	"golang.org/x/text/encoding/simplifiedchinese"
+	"golang.org/x/text/transform"
 )
 
 // LocationResponse represents the response from IP location API
@@ -74,7 +77,9 @@ func GetLocation(ctx context.Context, ip string) (province string, city string,
 		return "", "", fmt.Errorf("request failed with status: %d", resp.StatusCode)
 	}
 
-	body, err := io.ReadAll(resp.Body)
+	// API返回的是GBK编码，需要转换为UTF-8
+	utf8Reader := transform.NewReader(resp.Body, simplifiedchinese.GBK.NewDecoder())
+	body, err := io.ReadAll(utf8Reader)
 	if err != nil {
 		return "", "", fmt.Errorf("read response failed: %w", err)
 	}