fix: 后端代码格式化

backend/src/main/java/com/openisle/service/CaptchaService.java

@@ -4,11 +4,12 @@ package com.openisle.service;
  * Abstract service for verifying CAPTCHA tokens.
  */
 public abstract class CaptchaService {
-    /**
-     * Verify the CAPTCHA token sent from client.
-     *
-     * @param token CAPTCHA token
-     * @return true if token is valid
-     */
-    public abstract boolean verify(String token);
+
+  /**
+   * Verify the CAPTCHA token sent from client.
+   *
+   * @param token CAPTCHA token
+   * @return true if token is valid
+   */
+  public abstract boolean verify(String token);
 }