feat(mp): 微信模板消息订阅统一封装

- 新增 requestSubscribe() 统一订阅函数，消除页面内类型断言重复
- 用药页面新增 requestSubscribeMessage 订阅（MEDICATION_REMINDER 模板）
- 告警页面改用 requestSubscribe('CRITICAL_HEALTH_ALERT')
- wechat-templates 新增 MEDICATION_REMINDER 模板 ID 环境变量

apps/miniprogram/src/pages/pkg-profile/medication/index.tsx

@@ -3,6 +3,7 @@ import { View, Text, Input, Picker } from '@tarojs/components';
 import Taro from '@tarojs/taro';
 import { usePageData } from '@/hooks/usePageData';
 import { getCachedPatientId } from '@/services/request';
+import { requestSubscribe } from '@/services/wechat-templates';
 import EmptyState from '../../../components/EmptyState';
 import {
   listReminders,
@@ -36,7 +37,14 @@ export default function MedicationReminder() {
     }
   }, []);
 
-  usePageData(fetchReminders, { throttleMs: 5000, enablePullDown: true });
+  usePageData(
+    async () => {
+      await fetchReminders();
+      // 请求用药提醒推送订阅
+      requestSubscribe('MEDICATION_REMINDER');
+    },
+    { throttleMs: 5000, enablePullDown: true },
+  );
 
   const handleToggle = async (r: MedicationReminder) => {
     try {