refactor(App, navigation): migrate to Expo Router and clean up navigation structure

- Updated App entry point to utilize Expo Router, simplifying the navigation setup.
- Removed legacy navigation components and services to streamline the codebase.
- Adjusted package.json to reflect the new entry point and updated dependencies for compatibility.
- Enhanced overall application structure by consolidating navigation logic and improving maintainability.

src/screens/home/HomeScreen.tsx

@@ -19,8 +19,7 @@ import {
   Modal,
 } from 'react-native';
 import { SafeAreaView, useSafeAreaInsets } from 'react-native-safe-area-context';
-import { useNavigation } from '@react-navigation/native';
-import { NativeStackNavigationProp } from '@react-navigation/native-stack';
+import { useRouter } from 'expo-router';
 import { MaterialCommunityIcons } from '@expo/vector-icons';
 import { Gesture, GestureDetector } from 'react-native-gesture-handler';
 import { colors, spacing, borderRadius, shadows } from '../../theme';
@@ -31,15 +30,12 @@ import { postService } from '../../services';
 import { PostCard, TabBar, SearchBar } from '../../components/business';
 import type { PostCardAction } from '../../components/business/PostCard';
 import { Loading, EmptyState, Text, ImageGallery, ImageGridItem, ResponsiveGrid } from '../../components/common';
-import { HomeStackParamList, RootStackParamList } from '../../navigation/types';
 import { useResponsive, useResponsiveSpacing } from '../../hooks/useResponsive';
 import { useDifferentialPosts } from '../../hooks/useDifferentialPosts';
 import { processPostUseCase } from '../../core/usecases/ProcessPostUseCase';
 import { SearchScreen } from './SearchScreen';
 import { CreatePostScreen } from '../create/CreatePostScreen';
-import { navigationService } from '../../infrastructure/navigation/navigationService';
-
-type NavigationProp = NativeStackNavigationProp<HomeStackParamList, 'Home'> & NativeStackNavigationProp<RootStackParamList>;
+import * as hrefs from '../../navigation/hrefs';
 
 const TABS = ['最新', '关注', '热门'];
 const TAB_ICONS = ['clock-outline', 'account-heart-outline', 'fire'];
@@ -54,7 +50,7 @@ type ViewMode = 'list' | 'grid';
 type PostType = 'follow' | 'hot' | 'latest';
 
 export const HomeScreen: React.FC = () => {
-  const navigation = useNavigation<NavigationProp>();
+  const router = useRouter();
   const insets = useSafeAreaInsets();
   const { posts: storePosts } = useUserStore();
   const currentUser = useCurrentUser();
@@ -302,12 +298,12 @@ export const HomeScreen: React.FC = () => {
 
   // 跳转到帖子详情
   const handlePostPress = (postId: string, scrollToComments: boolean = false) => {
-    navigationService.navigate('PostDetail', { postId, scrollToComments });
+    router.push(hrefs.hrefPostDetail(postId, scrollToComments));
   };
 
   // 跳转到用户主页
   const handleUserPress = (userId: string) => {
-    navigationService.navigate('UserProfile', { userId });
+    router.push(hrefs.hrefUserProfile(userId));
   };
 
   // 点赞帖子
@@ -563,10 +559,12 @@ export const HomeScreen: React.FC = () => {
             />
           }
         >
-          {distributePostsToColumns.map((column, index) => renderWaterfallColumn(column, index))}
-          {/* 加载更多指示器 */}
-          {isLoading && displayPosts.length > 0 && (
-            <View style={styles.loadingMore}>
+          <View style={styles.waterfallColumnsRow}>
+            {distributePostsToColumns.map((column, index) => renderWaterfallColumn(column, index))}
+          </View>
+          {/* 独立底部加载区：避免参与横向列布局导致列宽抖动 */}
+          {isLoadingMore && displayPosts.length > 0 && (
+            <View style={styles.loadingMoreFooter}>
               <Loading size="sm" />
             </View>
           )}
@@ -808,8 +806,12 @@ const styles = StyleSheet.create({
     flex: 1,
   },
   waterfallContainer: {
-    flexDirection: 'row',
+    width: '100%',
     flexGrow: 1,
+  },
+  waterfallColumnsRow: {
+    width: '100%',
+    flexDirection: 'row',
     alignItems: 'flex-start',
   },
   waterfallColumn: {
@@ -844,7 +846,7 @@ const styles = StyleSheet.create({
     height: 72,
     borderRadius: 36,
   },
-  loadingMore: {
+  loadingMoreFooter: {
     paddingVertical: 20,
     alignItems: 'center',
     justifyContent: 'center',