fix(mp): setTimeout 无清理修复 — useSafeTimeout hook + 10 页面接入

新增 useSafeTimeout hook，页面隐藏时自动清理所有定时器。
10 个页面接入：daily-monitoring、exchange、family-add、
health/input、prescription detail/create、dialysis detail/create、
appointment detail/create。所有 fire-and-forget setTimeout 替换为
safeSetTimeout，避免页面切走后定时器回调在错误上下文执行。

apps/miniprogram/src/pages/pkg-mall/exchange/index.tsx

@@ -10,6 +10,7 @@ import type { PointsProduct } from '../../../services/points';
 import { usePointsStore } from '../../../stores/points';
 import Loading from '../../../components/Loading';
 import { useElderClass } from '../../../hooks/useElderClass';
+import { useSafeTimeout } from '@/hooks/useSafeTimeout';
 import './index.scss';
 
 const TYPE_INITIAL: Record<string, string> = {
@@ -37,6 +38,7 @@ export default function ExchangeConfirm() {
   const refreshPoints = usePointsStore((s) => s.refresh);
   const [loading, setLoading] = useState(true);
   const [submitting, setSubmitting] = useState(false);
+  const { safeSetTimeout } = useSafeTimeout();
 
   useThrottledDidShow(() => {
     Taro.setNavigationBarTitle({ title: '确认兑换' });
@@ -48,7 +50,7 @@ export default function ExchangeConfirm() {
     const productId = instance.router?.params?.product_id;
     if (!productId) {
       Taro.showToast({ title: '参数错误', icon: 'none' });
-      setTimeout(() => Taro.navigateBack(), 1500);
+      safeSetTimeout(() => Taro.navigateBack(), 1500);
       return;
     }
 
@@ -61,13 +63,13 @@ export default function ExchangeConfirm() {
       const found = productRes.data.find((p) => p.id === productId);
       if (!found) {
         Taro.showToast({ title: '商品不存在', icon: 'none' });
-        setTimeout(() => Taro.navigateBack(), 1500);
+        safeSetTimeout(() => Taro.navigateBack(), 1500);
         return;
       }
       setProduct(found);
     } catch {
       Taro.showToast({ title: '加载失败', icon: 'none' });
-      setTimeout(() => Taro.navigateBack(), 1500);
+      safeSetTimeout(() => Taro.navigateBack(), 1500);
     } finally {
       setLoading(false);
     }
@@ -96,7 +98,7 @@ export default function ExchangeConfirm() {
       const order = await exchangeProduct(product.id);
       Taro.showToast({ title: '兑换成功', icon: 'success', duration: 2000 });
 
-      setTimeout(() => {
+      safeSetTimeout(() => {
         Taro.showModal({
           title: '兑换成功',
           content: `核销码: ${order.qr_code}\n请凭此码到前台核销`,