Refactor SMTP config usage in EmailQueue

Move SMTP configuration retrieval from class initialization to method scope in send_email_by_smtp. This improves encapsulation and ensures the latest settings are used when sending emails.

app/service/email_queue.py

@@ -33,14 +33,6 @@ class EmailQueue:
         # 邮件提供商配置
         self.email_provider = settings.email_provider
 
-        # SMTP 邮件配置
-        self.smtp_server = settings.smtp_server
-        self.smtp_port = settings.smtp_port
-        self.smtp_username = settings.smtp_username
-        self.smtp_password = settings.smtp_password
-        self.from_email = settings.from_email
-        self.from_name = settings.from_name
-
         # MailerSend 服务（延迟初始化）
         self._mailersend_service = None
 
@@ -240,9 +232,17 @@ class EmailQueue:
             是否发送成功
         """
         try:
+            # 获取 SMTP 配置
+            smtp_server = settings.smtp_server
+            smtp_port = settings.smtp_port
+            smtp_username = settings.smtp_username
+            smtp_password = settings.smtp_password
+            from_email = settings.from_email
+            from_name = settings.from_name
+
             # 创建邮件
             msg = MIMEMultipart("alternative")
-            msg["From"] = f"{self.from_name} <{self.from_email}>"
+            msg["From"] = f"{from_name} <{from_email}>"
             msg["To"] = email_data.get("to_email", "")
             msg["Subject"] = email_data.get("subject", "")
 
@@ -258,10 +258,10 @@ class EmailQueue:
 
             # 发送邮件 - 使用线程池避免阻塞事件循环
             def send_smtp_email():
-                with smtplib.SMTP(self.smtp_server, self.smtp_port) as server:
-                    if self.smtp_username and self.smtp_password:
+                with smtplib.SMTP(smtp_server, smtp_port) as server:
+                    if smtp_username and smtp_password:
                         server.starttls()
-                        server.login(self.smtp_username, self.smtp_password)
+                        server.login(smtp_username, smtp_password)
                     server.send_message(msg)
 
             await self._run_in_executor(send_smtp_email)