refactor: centralize email internationalization handling (#22752)

Co-authored-by: Claude <noreply@anthropic.com>

api/schedule/mail_clean_document_notify_task.py

@@ -3,12 +3,12 @@ import time
 from collections import defaultdict
 
 import click
-from flask import render_template  # type: ignore
 
 import app
 from configs import dify_config
 from extensions.ext_database import db
 from extensions.ext_mail import mail
+from libs.email_i18n import EmailType, get_email_i18n_service
 from models.account import Account, Tenant, TenantAccountJoin
 from models.dataset import Dataset, DatasetAutoDisableLog
 from services.feature_service import FeatureService
@@ -72,14 +72,16 @@ def mail_clean_document_notify_task():
                         document_count = len(document_ids)
                         knowledge_details.append(rf"Knowledge base {dataset.name}: {document_count} documents")
                 if knowledge_details:
-                    html_content = render_template(
-                        "clean_document_job_mail_template-US.html",
-                        userName=account.email,
-                        knowledge_details=knowledge_details,
-                        url=url,
-                    )
-                    mail.send(
-                        to=account.email, subject="Dify Knowledge base auto disable notification", html=html_content
+                    email_service = get_email_i18n_service()
+                    email_service.send_email(
+                        email_type=EmailType.DOCUMENT_CLEAN_NOTIFY,
+                        language_code="en-US",
+                        to=account.email,
+                        template_context={
+                            "userName": account.email,
+                            "knowledge_details": knowledge_details,
+                            "url": url,
+                        },
                     )
 
             # update notified to True