fix:解决ai助手文件下载请求中文路径下载失败问题

service/controllers/aiChatControllers.go

@@ -6,6 +6,7 @@ import (
 	"encoding/json"
 	"fmt"
 	"io"
+	"net/url"
 	"os/user"
 	"path/filepath"
 	"sort"
@@ -366,7 +367,10 @@ func DownloadAiFile(c *fiber.Ctx) error {
 		fileName = fileName[9:]
 	}
 
-	c.Set("Content-Disposition", fmt.Sprintf(`attachment; filename="%s"`, fileName))
+	// 文件名可能含中文/非 ASCII，必须做 RFC 5987 编码后再写入响应头，
+	// 否则 Content-Disposition 含非法非 ASCII 字节，nginx 会判定 upstream 响应头非法而返回 502。
+	encoded := url.PathEscape(fileName)
+	c.Set("Content-Disposition", fmt.Sprintf("attachment; filename=%s; filename*=UTF-8''%s", encoded, encoded))
 	c.Set("Content-Type", stat.ContentType)
 	return c.Send(data)
 }