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

components/challenges/ChallengeRankingItem.tsx

@@ -1,3 +1,4 @@
+import { useI18n } from '@/hooks/useI18n';
 import type { RankingItem } from '@/store/challengesSlice';
 import { Ionicons } from '@expo/vector-icons';
 import { Image } from 'expo-image';
@@ -18,34 +19,34 @@ const formatNumber = (value: number): string => {
   return value.toFixed(2).replace(/0+$/, '').replace(/\.$/, '');
 };
 
-const formatMinutes = (value: number): string => {
-  const safeValue = Math.max(0, Math.round(value));
-  const hours = safeValue / 60;
-  return `${hours.toFixed(1)} 小时`;
-};
-
-const formatValueWithUnit = (value: number | undefined, unit?: string): string | undefined => {
-  if (typeof value !== 'number' || Number.isNaN(value)) {
-    return undefined;
-  }
-  if (unit === 'min') {
-    return formatMinutes(value);
-  }
-  const formatted = formatNumber(value);
-  return unit ? `${formatted} ${unit}` : formatted;
-};
-
 export function ChallengeRankingItem({ item, index, showDivider = false, unit }: ChallengeRankingItemProps) {
-  console.log('unit', unit);
+  const { t } = useI18n();
+
+  const formatMinutes = (value: number): string => {
+    const safeValue = Math.max(0, Math.round(value));
+    const hours = safeValue / 60;
+    return `${hours.toFixed(1)} ${t('challengeDetail.ranking.hour')}`;
+  };
+
+  const formatValueWithUnit = (value: number | undefined, unit?: string): string | undefined => {
+    if (typeof value !== 'number' || Number.isNaN(value)) {
+      return undefined;
+    }
+    if (unit === 'min') {
+      return formatMinutes(value);
+    }
+    const formatted = formatNumber(value);
+    return unit ? `${formatted} ${unit}` : formatted;
+  };
 
   const reportedLabel = formatValueWithUnit(item.todayReportedValue, unit);
   const targetLabel = formatValueWithUnit(item.todayTargetValue, unit);
   const progressLabel = reportedLabel && targetLabel
-    ? `今日 ${reportedLabel} / ${targetLabel}`
+    ? `${t('challengeDetail.ranking.today')} ${reportedLabel} / ${targetLabel}`
     : reportedLabel
-      ? `今日 ${reportedLabel}`
+      ? `${t('challengeDetail.ranking.today')} ${reportedLabel}`
       : targetLabel
-        ? `今日目标 ${targetLabel}`
+        ? `${t('challengeDetail.ranking.todayGoal')} ${targetLabel}`
         : undefined;
 
   return (