feat(challenges): 新增挑战鼓励提醒后台任务与通知支持

- 在 backgroundTaskManager 中增加 executeChallengeReminderTask，每日检查已加入且未打卡的挑战并发送鼓励通知
- 扩展 ChallengeNotificationHelpers 提供 sendEncouragementNotification 方法
- 新增 NotificationTypes.CHALLENGE_ENCOURAGEMENT 及对应点击跳转处理
- challengesApi 补充 checkedInToday 字段用于判断今日是否已打卡
- 临时注释掉挑战列表与详情页头部的礼物/分享按钮，避免干扰主流程

services/backgroundTaskManager.ts

@@ -1,7 +1,8 @@
 import { store } from '@/store';
 import AsyncStorage from '@/utils/kvStore';
 import { log } from '@/utils/logger';
-import { StandReminderHelpers, WaterNotificationHelpers } from '@/utils/notificationHelpers';
+import { listChallenges } from '@/services/challengesApi';
+import { ChallengeNotificationHelpers, StandReminderHelpers, WaterNotificationHelpers } from '@/utils/notificationHelpers';
 import * as BackgroundTask from 'expo-background-task';
 import * as TaskManager from 'expo-task-manager';
 import { TaskManagerTaskBody } from 'expo-task-manager';
@@ -99,6 +100,55 @@ async function executeStandReminderTask(): Promise<void> {
   }
 }
 
+async function executeChallengeReminderTask(): Promise<void> {
+  try {
+    console.log('执行挑战鼓励提醒后台任务...');
+
+    const state = store.getState();
+    const normalizedUserName = state.user.profile?.name?.trim();
+    const userName = normalizedUserName && normalizedUserName.length > 0 ? normalizedUserName : '朋友';
+
+    const challenges = await listChallenges();
+    const joinedChallenges = challenges.filter((challenge) => challenge.isJoined && challenge.progress);
+
+    if (!joinedChallenges.length) {
+      console.log('没有加入的挑战或挑战没有进度，跳过挑战提醒');
+      return;
+    }
+
+    const todayKey = new Date().toISOString().slice(0, 10);
+
+    for (const challenge of joinedChallenges) {
+      const progress = challenge.progress;
+      if (!progress || progress.checkedInToday) {
+        continue;
+      }
+
+      const storageKey = `@challenge_encouragement_sent:${challenge.id}`;
+      const lastSent = await AsyncStorage.getItem(storageKey);
+      if (lastSent === todayKey) {
+        continue;
+      }
+
+      try {
+        await ChallengeNotificationHelpers.sendEncouragementNotification({
+          userName,
+          challengeTitle: challenge.title,
+          challengeId: challenge.id,
+        });
+
+        await AsyncStorage.setItem(storageKey, todayKey);
+      } catch (notificationError) {
+        console.error('发送挑战鼓励通知失败:', notificationError);
+      }
+    }
+
+    console.log('挑战鼓励提醒后台任务完成');
+  } catch (error) {
+    console.error('执行挑战鼓励提醒后台任务失败:', error);
+  }
+}
+
 // 发送测试通知以验证后台任务执行
 async function sendTestNotification(): Promise<void> {
   try {
@@ -149,6 +199,8 @@ async function executeBackgroundTasks(): Promise<void> {
     // 执行站立提醒检查任务
     // await executeStandReminderTask();
 
+    await executeChallengeReminderTask();
+
     console.log('后台任务执行完成');
   } catch (error) {
     console.error('执行后台任务失败:', error);