feat(mp): 患者端健康告警页面 + 首页入口

P1-8: 小程序患者告警推送
  - 新增 alert service：listPatientAlerts 按患者 ID 查询告警
  - 新增 pkg-health/alerts 告警列表页：严重程度标签 + 状态过滤 + 分页
  - 首页快捷服务新增"健康告警"入口
  - app.config.ts 注册 alerts/index 页面路由

apps/miniprogram/src/services/alert.ts

@@ -0,0 +1,21 @@
+import { api } from './request';
+
+export interface Alert {
+  id: string;
+  severity: string;
+  title: string;
+  status: string;
+  detail?: Record<string, unknown>;
+  created_at: string;
+  acknowledged_at?: string;
+  resolved_at?: string;
+}
+
+export async function listPatientAlerts(patientId: string, params?: { status?: string; page?: number; page_size?: number }) {
+  return api.get<{ data: Alert[]; total: number }>('/health/alerts', {
+    patient_id: patientId,
+    page: params?.page ?? 1,
+    page_size: params?.page_size ?? 20,
+    status: params?.status,
+  });
+}