feat: Implement browserless Codex API authentication with PoW solving and a new mail service, and update gitignore to exclude get_code.go.

backend/internal/mail/service.go

@@ -129,6 +129,7 @@ type EmailListResponse struct {
 
 // EmailItem 邮件项
 type EmailItem struct {
+	EmailID int    `json:"emailId"`
 	Content string `json:"content"`
 	Text    string `json:"text"`
 	Subject string `json:"subject"`
@@ -504,3 +505,57 @@ func GetVerificationCode(email string, timeout time.Duration) (string, error) {
 	client := NewClientForEmail(email)
 	return client.WaitForCode(email, timeout)
 }
+
+// GetLatestEmailID 获取邮箱最新邮件的ID
+// 基于 get_code.go 的实现，用于在发送验证码请求前记录最新邮件ID
+func GetLatestEmailID(email string) int {
+	client := NewClientForEmail(email)
+	emails, err := client.GetEmails(email, 1)
+	if err != nil || len(emails) == 0 {
+		return 0
+	}
+	return emails[0].EmailID
+}
+
+// GetEmailOTPAfterID 获取指定邮件ID之后的OTP验证码
+// 基于 get_code.go 的实现，只获取 afterEmailID 之后的新邮件中的验证码
+func GetEmailOTPAfterID(email string, afterEmailID int, timeout time.Duration) (string, error) {
+	client := NewClientForEmail(email)
+	start := time.Now()
+	codeRegex := regexp.MustCompile(`\b(\d{6})\b`)
+
+	for time.Since(start) < timeout {
+		emails, err := client.GetEmails(email, 5)
+		if err == nil {
+			for _, mail := range emails {
+				// 只处理 afterEmailID 之后的新邮件
+				if mail.EmailID <= afterEmailID {
+					continue
+				}
+
+				subject := strings.ToLower(mail.Subject)
+				// 匹配 OpenAI/ChatGPT 验证码邮件
+				if !strings.Contains(subject, "code") {
+					continue
+				}
+
+				// 从标题提取验证码
+				if matches := codeRegex.FindStringSubmatch(mail.Subject); len(matches) >= 2 {
+					return matches[1], nil
+				}
+
+				// 从内容提取验证码
+				content := mail.Content
+				if content == "" {
+					content = mail.Text
+				}
+				if matches := codeRegex.FindStringSubmatch(content); len(matches) >= 2 {
+					return matches[1], nil
+				}
+			}
+		}
+		time.Sleep(1 * time.Second)
+	}
+
+	return "", fmt.Errorf("验证码获取超时 (afterEmailID=%d)", afterEmailID)
+}