feat(i18n): 全面实现应用核心功能模块的国际化支持

- 新增 i18n 翻译资源，覆盖睡眠、饮水、体重、锻炼、用药 AI 识别、步数、健身圆环、基础代谢及设置等核心模块
- 重构相关页面及组件（如 SleepDetail, WaterDetail, WorkoutHistory 等）使用 `useI18n` 钩子替换硬编码文本
- 升级 `utils/date` 工具库与 `DateSelector` 组件，支持基于语言环境的日期格式化与显示
- 完善登录页、注销流程及权限申请弹窗的双语提示信息
- 优化部分页面的 UI 细节与字体样式以适配多语言显示

app/challenges/[id]/leaderboard.tsx

@@ -4,6 +4,7 @@ import { HeaderBar } from '@/components/ui/HeaderBar';
 import { Colors } from '@/constants/Colors';
 import { useAppDispatch, useAppSelector } from '@/hooks/redux';
 import { useColorScheme } from '@/hooks/useColorScheme';
+import { useI18n } from '@/hooks/useI18n';
 import { useSafeAreaTop } from '@/hooks/useSafeAreaWithPadding';
 import {
   fetchChallengeDetail,
@@ -37,6 +38,7 @@ export default function ChallengeLeaderboardScreen() {
   const theme = (useColorScheme() ?? 'light') as 'light' | 'dark';
   const colorTokens = Colors[theme];
   const insets = useSafeAreaInsets();
+  const { t } = useI18n();
 
   const challengeSelector = useMemo(() => (id ? selectChallengeById(id) : undefined), [id]);
   const challenge = useAppSelector((state) => (challengeSelector ? challengeSelector(state) : undefined));
@@ -75,12 +77,12 @@ export default function ChallengeLeaderboardScreen() {
   if (!id) {
     return (
       <View style={[styles.safeArea, { backgroundColor: colorTokens.background }]}>
-        <HeaderBar title="排行榜" onBack={() => router.back()} withSafeTop />
+        <HeaderBar title={t('challengeDetail.leaderboard.title')} onBack={() => router.back()} withSafeTop />
         <View style={{
           paddingTop: safeAreaTop
         }} />
         <View style={styles.missingContainer}>
-          <Text style={[styles.missingText, { color: colorTokens.textSecondary }]}>未找到该挑战。</Text>
+          <Text style={[styles.missingText, { color: colorTokens.textSecondary }]}>{t('challengeDetail.leaderboard.notFound')}</Text>
         </View>
       </View>
     );
@@ -89,10 +91,10 @@ export default function ChallengeLeaderboardScreen() {
   if (detailStatus === 'loading' && !challenge) {
     return (
       <View style={[styles.safeArea, { backgroundColor: '#f3f4fb' }]}>
-        <HeaderBar title="排行榜" onBack={() => router.back()} withSafeTop />
+        <HeaderBar title={t('challengeDetail.leaderboard.title')} onBack={() => router.back()} withSafeTop />
         <View style={styles.loadingContainer}>
           <ActivityIndicator color={colorTokens.primary} />
-          <Text style={[styles.loadingText, { color: colorTokens.textSecondary }]}>加载榜单中…</Text>
+          <Text style={[styles.loadingText, { color: colorTokens.textSecondary }]}>{t('challengeDetail.leaderboard.loading')}</Text>
         </View>
       </View>
     );
@@ -131,10 +133,10 @@ export default function ChallengeLeaderboardScreen() {
   if (!challenge) {
     return (
       <View style={[styles.safeArea, { backgroundColor: '#f3f4fb' }]}>
-        <HeaderBar title="排行榜" onBack={() => router.back()} withSafeTop />
+        <HeaderBar title={t('challengeDetail.leaderboard.title')} onBack={() => router.back()} withSafeTop />
         <View style={styles.missingContainer}>
           <Text style={[styles.missingText, { color: colorTokens.textSecondary }]}>
-            {detailError ?? '暂时无法加载榜单，请稍后再试。'}
+            {detailError ?? t('challengeDetail.leaderboard.loadFailed')}
           </Text>
         </View>
       </View>
@@ -146,7 +148,7 @@ export default function ChallengeLeaderboardScreen() {
 
   return (
     <View style={[styles.safeArea, { backgroundColor: '#f3f4fb' }]}>
-      <HeaderBar title="排行榜" onBack={() => router.back()} withSafeTop />
+      <HeaderBar title={t('challengeDetail.leaderboard.title')} onBack={() => router.back()} withSafeTop />
       <ScrollView
         style={styles.scrollView}
         contentContainerStyle={{ paddingBottom: insets.bottom + 40, paddingTop: safeAreaTop }}
@@ -178,7 +180,7 @@ export default function ChallengeLeaderboardScreen() {
           {showInitialRankingLoading ? (
             <View style={styles.rankingLoading}>
               <ActivityIndicator color={colorTokens.primary} />
-              <Text style={[styles.loadingText, { color: colorTokens.textSecondary }]}>加载榜单中…</Text>
+              <Text style={[styles.loadingText, { color: colorTokens.textSecondary }]}>{t('challengeDetail.leaderboard.loading')}</Text>
             </View>
           ) : rankingData.length ? (
             rankingData.map((item, index) => (
@@ -196,18 +198,18 @@ export default function ChallengeLeaderboardScreen() {
             </View>
           ) : (
             <View style={styles.emptyRanking}>
-              <Text style={styles.emptyRankingText}>榜单即将开启，快来抢占席位。</Text>
+              <Text style={styles.emptyRankingText}>{t('challengeDetail.leaderboard.empty')}</Text>
             </View>
           )}
           {isLoadingMore ? (
             <View style={styles.loadMoreIndicator}>
               <ActivityIndicator color={colorTokens.primary} size="small" />
-              <Text style={[styles.loadingText, { color: colorTokens.textSecondary, marginTop: 8 }]}>加载更多…</Text>
+              <Text style={[styles.loadingText, { color: colorTokens.textSecondary, marginTop: 8 }]}>{t('challengeDetail.leaderboard.loadMore')}</Text>
             </View>
           ) : null}
           {rankingLoadMoreStatus === 'failed' ? (
             <View style={styles.loadMoreIndicator}>
-              <Text style={styles.loadMoreErrorText}>加载更多失败，请下拉刷新重试</Text>
+              <Text style={styles.loadMoreErrorText}>{t('challengeDetail.leaderboard.loadMoreFailed')}</Text>
             </View>
           ) : null}
         </View>