feat(mp): App 级告警长轮询 + 健康总览 TS 修复

- 新增 useAlertPolling hook：10s 间隔轮询 critical 告警
- requestUnlimited 独立通道，不占并发槽位
- generation counter 防重叠 + 失败指数退避(max 30s/10次)
- 新告警弹窗 Taro.showModal + TabBar 角标
- 修复 HealthThreshold 属性名(indicator/level 非 indicator_name/severity)
- 修复 usePageData fetchData 返回类型

apps/miniprogram/src/hooks/useAlertPolling.ts

@@ -0,0 +1,123 @@
+import { useRef, useCallback } from 'react';
+import Taro from '@tarojs/taro';
+import { useDidShow, useDidHide } from '@tarojs/taro';
+import { requestUnlimited } from '@/services/request';
+import { useAuthStore } from '@/stores/auth';
+import type { Alert } from '@/services/alert';
+
+interface PollState {
+  generation: number;
+  timer: ReturnType<typeof setTimeout> | null;
+  failCount: number;
+  lastAlertCount: number;
+}
+
+const POLL_INTERVAL = 10_000;
+const MAX_FAILURES = 10;
+const FAIL_BACKOFF_BASE = 2000;
+const FAIL_BACKOFF_MAX = 30_000;
+
+/**
+ * App 级告警长轮询。
+ *
+ * - 登录态 + 有 patientId 时启动
+ * - 使用 requestUnlimited 走独立通道，不占并发槽位
+ * - generation counter 防止重叠
+ * - useDidShow/Hide 控制前后台
+ * - critical 告警弹窗提醒 + TabBar 角标
+ */
+export function useAlertPolling() {
+  const stateRef = useRef<PollState>({
+    generation: 0,
+    timer: null,
+    failCount: 0,
+    lastAlertCount: 0,
+  });
+
+  const patientId = useAuthStore((s) => s.currentPatient?.id);
+  const isLoggedIn = useAuthStore((s) => !!s.user);
+  const enabled = isLoggedIn && !!patientId;
+
+  const poll = useCallback(async (gen: number, failCount: number) => {
+    const s = stateRef.current;
+    if (gen !== s.generation) return;
+    if (failCount >= MAX_FAILURES) return;
+
+    try {
+      const pid = useAuthStore.getState().currentPatient?.id;
+      if (!pid) return;
+
+      const res = await requestUnlimited<{ data: Alert[]; total: number }>(
+        'GET',
+        `/health/alerts?patient_id=${pid}&status=pending&severity=critical&page=1&page_size=5`,
+        undefined,
+        8000,
+      );
+
+      if (gen !== s.generation) return;
+
+      const count = res.total ?? 0;
+
+      // TabBar 角标
+      try {
+        if (count > 0) {
+          Taro.setTabBarBadge({ index: 2, text: String(count) });
+        } else {
+          Taro.removeTabBarBadge({ index: 2 });
+        }
+      } catch { /* TabBar 可能不存在 */ }
+
+      // 告警数量增加时弹窗提醒
+      if (count > s.lastAlertCount) {
+        Taro.showModal({
+          title: '健康告警',
+          content: `您有 ${count} 条待处理的危急值告警，请及时关注`,
+          showCancel: false,
+          confirmText: '知道了',
+        });
+      }
+      s.lastAlertCount = count;
+
+      failCount = 0;
+    } catch {
+      failCount++;
+    }
+
+    if (gen !== s.generation) return;
+    const delay = failCount > 0 ? Math.min(failCount * FAIL_BACKOFF_BASE, FAIL_BACKOFF_MAX) : POLL_INTERVAL;
+    s.timer = setTimeout(() => {
+      if (gen === s.generation) poll(gen, failCount);
+    }, delay);
+  }, []);
+
+  const start = useCallback(() => {
+    const s = stateRef.current;
+    s.generation++;
+    s.failCount = 0;
+    if (s.timer) { clearTimeout(s.timer); s.timer = null; }
+    poll(s.generation, 0);
+  }, [poll]);
+
+  const stop = useCallback(() => {
+    const s = stateRef.current;
+    s.generation++;
+    if (s.timer) { clearTimeout(s.timer); s.timer = null; }
+    try { Taro.removeTabBarBadge({ index: 2 }); } catch { /* ignore */ }
+  }, []);
+
+  useDidShow(() => {
+    if (enabled) start();
+  });
+
+  useDidHide(() => {
+    stop();
+  });
+
+  // enabled 变化时启停
+  const prevEnabledRef = useRef(enabled);
+  if (enabled !== prevEnabledRef.current) {
+    prevEnabledRef.current = enabled;
+    if (enabled) start();
+    else stop();
+  }
+}