feat(auth): 预加载用户数据并优化登录状态同步

- 在启动屏预加载用户 token 与资料，避免首页白屏
- 新增 rehydrateUserSync 同步注入 Redux，减少异步等待
- 登录页兼容 ERR_REQUEST_CANCELED 取消场景
- 各页面统一依赖 isLoggedIn 判断，移除冗余控制台日志
- 步数卡片与详情页改为实时拉取健康数据，不再缓存至 Redux
- 后台任务注册移至顶层，防止重复定义
- 体重记录、HeaderBar 等 UI 细节样式微调

components/weight/WeightRecordCard.tsx

@@ -69,7 +69,7 @@ export const WeightRecordCard: React.FC<WeightRecordCardProps> = ({
       overshootRight={false}
     >
       <View
-        style={[styles.recordCard, colorScheme === 'dark' && styles.recordCardDark]}
+        style={[styles.recordCard]}
       >
         <View style={styles.recordHeader}>
           <Text style={[styles.recordDateTime, { color: themeColors.textSecondary }]}>
@@ -111,14 +111,11 @@ export const WeightRecordCard: React.FC<WeightRecordCardProps> = ({
 
 const styles = StyleSheet.create({
   recordCard: {
-    backgroundColor: '#F0F0F0',
+    backgroundColor: '#ffffff',
     borderRadius: 16,
     padding: 20,
     marginBottom: 12,
   },
-  recordCardDark: {
-    backgroundColor: '#1F2937',
-  },
   recordHeader: {
     flexDirection: 'row',
     justifyContent: 'space-between',
@@ -145,8 +142,8 @@ const styles = StyleSheet.create({
     fontWeight: '500',
   },
   recordWeightValue: {
-    fontSize: 18,
-    fontWeight: '700',
+    fontSize: 16,
+    fontWeight: '600',
     color: '#192126',
     marginLeft: 4,
     flex: 1,