feat(EmailService): 添加邮件附件功能并更新单元测试

- 在 EmailService 类的 sendHtml 方法中添加了附件处理逻辑
- 更新了 EmailServiceTest 单元测试，增加了附件发送的测试用例
- 优化了测试用例的结构，提高了可读性和可维护性

src/Service/EmailService.php

@@ -130,6 +130,8 @@ class EmailService
         string $html,
         array $cc = [],
         array $bcc = [],
+        array $attachmentPaths = [],
+        array $attachments = [],
         int $priority = Email::PRIORITY_NORMAL
     ): bool {
         $email = (new Email())
@@ -141,6 +143,22 @@ class EmailService
             ->subject($subject)
             ->html($html);
 
+        foreach ($attachmentPaths as $attachmentPath) {
+            if (is_string($attachmentPath)) {
+                $email = $email->attachFromPath($attachmentPath);
+            } else {
+                $email = $email->attachFromPath($attachmentPath['path'], $attachmentPath['name'] ?? null, $attachmentPath['mimeType'] ?? null);
+            }
+        }
+
+        foreach ($attachments as $attachment) {
+            if (is_string($attachment)) {
+                $email = $email->attach($attachment);
+            } else {
+                $email = $email->attach($attachment['content'], $attachment['name'] ?? null, $attachment['mimeType'] ?? null);
+            }
+        }
+
         $this->mailer->send($email);
 
         return true;