fix: 更新卡片时补充 main_title 字段，修复 errcode 41016

企微更新模板卡片接口要求包含 main_title，否则报 missing title 错误。

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

app/services/wechat_service.py

@@ -228,6 +228,10 @@ class WeChatService:
                 "template_card": {
                     "card_type": "button_interaction",
                     "task_id": alarm_id,
+                    "main_title": {
+                        "title": replace_text,
+                    },
+                    "sub_title_text": f"操作人：{operator_name}",
                     "button_list": [
                         {
                             "text": replace_text,