feat: 更新应用名称和图标，优化用户界面

- 将应用名称修改为“Health Bot”，提升品牌识别度
- 更新应用图标为 logo.png，确保视觉一致性
- 删除不再使用的 ai-coach-chat 页面，简化代码结构
- 更新多个页面的导航和按钮文本，提升用户体验
- 添加体重历史记录功能，支持用户追踪健康数据
- 优化 Redux 状态管理，确保数据处理的准确性和稳定性

app/(tabs)/index.tsx

@@ -8,9 +8,10 @@ import { useAppDispatch, useAppSelector } from '@/hooks/redux';
 import { useColorScheme } from '@/hooks/useColorScheme';
 import { listRecommendedArticles } from '@/services/articles';
 import { fetchRecommendations, RecommendationType } from '@/services/recommendations';
-import { loadPlans, type TrainingPlan } from '@/store/trainingPlanSlice';
+import { loadPlans } from '@/store/trainingPlanSlice';
 // Removed WorkoutCard import since we no longer use the horizontal carousel
 import { useAuthGuard } from '@/hooks/useAuthGuard';
+import { TrainingPlan } from '@/services/trainingPlanApi';
 import { getChineseGreeting } from '@/utils/date';
 import { useRouter } from 'expo-router';
 import React from 'react';
@@ -29,7 +30,7 @@ export default function HomeScreen() {
   const { width: windowWidth, height: windowHeight } = useWindowDimensions();
 
   // 训练计划状态
-  const { plans, currentId } = useAppSelector((s) => s.trainingPlan);
+  const { plans } = useAppSelector((s) => s.trainingPlan);
   const [activePlan, setActivePlan] = React.useState<TrainingPlan | null>(null);
 
   // Draggable coach badge state
@@ -148,13 +149,13 @@ export default function HomeScreen() {
 
   // 获取激活的训练计划
   React.useEffect(() => {
-    if (isLoggedIn && currentId && plans.length > 0) {
-      const currentPlan = plans.find(p => p.id === currentId);
+    if (isLoggedIn && plans.length > 0) {
+      const currentPlan = plans.find(p => p.isActive);
       setActivePlan(currentPlan || null);
     } else {
       setActivePlan(null);
     }
-  }, [isLoggedIn, currentId, plans]);
+  }, [isLoggedIn, plans]);
 
   // 拉取推荐接口（已登录时）
   React.useEffect(() => {