fix(miniprogram): 关怀模式非线性放大重构 + 3 页面接入

- elder-mode.scss: 等比×1.3改为非线性放大（标题×1.15/正文×1.35/辅助×1.55）
- 体征网格从2列改为1列，解决放大后溢出问题
- 行高从1.5提升到1.7，对比度$tx3→$tx2增强可读性
- 健康页/消息页/咨询页接入useUIStore关怀模式
- 共享组件(EmptyState/ErrorState/Loading/StepIndicator)适配关怀模式
- 触控区域统一提升到56px+

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

apps/miniprogram/src/pages/health/index.tsx

@@ -3,6 +3,7 @@ import { View, Text, Input } from '@tarojs/components';
 import Taro, { useDidShow, usePullDownRefresh } from '@tarojs/taro';
 import { useHealthStore } from '../../stores/health';
 import { useAuthStore } from '../../stores/auth';
+import { useUIStore } from '../../stores/ui';
 import { inputVitalSign, getTrend, getHealthThresholds, findThreshold, DEFAULT_THRESHOLDS, type HealthThreshold } from '../../services/health';
 import { listPendingSuggestions, type AiSuggestionItem } from '../../services/ai-analysis';
 import Loading from '../../components/Loading';
@@ -42,6 +43,8 @@ interface TrendPoint {
 export default function Health() {
   const { todaySummary, loading, refreshToday, getTrend: fetchTrend } = useHealthStore();
   const { user, currentPatient } = useAuthStore();
+  const { mode } = useUIStore();
+  const modeClass = mode === 'elder' ? 'elder-mode' : '';
   const [activeTab, setActiveTab] = useState<VitalType>('blood_pressure');
   const [systolic, setSystolic] = useState('');
   const [diastolic, setDiastolic] = useState('');
@@ -211,7 +214,7 @@ export default function Health() {
   const dayLabels = ['日', '一', '二', '三', '四', '五', '六'];
 
   return (
-    <View className='health-page'>
+    <View className={`health-page ${modeClass}`}>
       {/* 页头 */}
       <View className='health-header'>
         <Text className='health-title'>健康数据</Text>