feat: 注册验证码改为自动生成图形验证码

1. Common.php: 新增captcha()接口,生成算术验证码图片(base64)
2. Common.php: 新增checkCaptcha()静态方法,验证码校验+防重放
3. User.php: 注册接口移除邮箱/短信OTP验证,改用图形验证码
验证码5分钟过期,验证后立即销毁

application/api/controller/User.php

@@ -141,21 +141,23 @@ class User extends Api
         $mobile = $this->request->post('mobile',"");
         $m_prefix = $this->request->post('m_prefix',"");
         $code = $this->request->post('code');
+        $captcha_key = $this->request->post('captcha_key', '');
         $pwd2 = $this->request->post('pay_pwd');
         $referral_code = $this->request->post('referral_code', '');
 
+        // 验证图形验证码（替代邮箱/短信OTP）
+        if (!$captcha_key || !$code) {
+            $this->error(__('验证码错误'));
+        }
+        $captchaOk = \app\api\controller\Common::checkCaptcha($captcha_key, $code);
+        if (!$captchaOk) {
+            $this->error(__('验证码错误'));
+        }
+
         if($mobile){
-            $ret = Sms::check($mobile, $code, 'register');
-            if (!$ret && $code!=157258) {
-                $this->error(__('验证码错误'));
-            }
             $username = $mobile;
             $extend['m_prefix'] = $m_prefix;
         }else{
-            $ret = Ems::check($email, $code, 'register');
-            if (!$ret && $code!=157258) {
-                $this->error(__('验证码错误'));
-            }
             $username = $email;
             $extend['m_prefix'] = "";
         }