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/appointment/create/index.tsx

@@ -8,6 +8,7 @@ import { trackEvent } from '@/services/analytics';
 import StepIndicator from '../../../components/StepIndicator';
 import WeekCalendar from '../../../components/WeekCalendar';
 import { useElderClass } from '../../../hooks/useElderClass';
+import { useSafeTimeout } from '@/hooks/useSafeTimeout';
 import './index.scss';
 
 const DEPARTMENTS = [
@@ -43,6 +44,7 @@ export default function AppointmentCreate() {
   const [timeSlot, setTimeSlot] = useState('');
   const [reason, setReason] = useState('');
   const [loading, setLoading] = useState(false);
+  const { safeSetTimeout } = useSafeTimeout();
   const [schedules, setSchedules] = useState<any[]>([]);
   const [timeSlots, setTimeSlots] = useState<TimeSlot[]>([]);
   const modeClass = useElderClass();
@@ -127,7 +129,7 @@ export default function AppointmentCreate() {
           await (Taro.requestSubscribeMessage as any)({ tmplIds: [tmplId] });
         } catch { /* 用户拒绝 */ }
       }
-      setTimeout(() => Taro.navigateBack(), 1500);
+      safeSetTimeout(() => Taro.navigateBack(), 1500);
     } catch {
       Taro.showToast({ title: '预约失败', icon: 'none' });
     } finally {