feat(ui): improve navigation, component props, and chat logic

- update `app.json` with splash screen configuration
- implement tab navigation redirection in `TabsLayout` for apps and profile tabs
- update `HighlightText` prop usage from `style` to `highlightStyle` in `PostCard` and `PostContentRenderer`
- fix chat message segment construction to avoid empty text segments when sending only images
- refine UI styling by removing unnecessary shadows and adjusting `UserScreen` header visibility
- improve `HomeScreen` scroll behavior by disabling animation on FlashList scroll-to-top

src/components/business/PostCard/PostCard.tsx

@@ -662,7 +662,7 @@ const PostCardInner: React.FC<PostCardProps> = (normalizedProps) => {
         ) : (
           <View style={styles.gridNoImagePreview}>
             <Text style={styles.gridNoImageText} numberOfLines={6}>
-              {highlightKeyword ? <HighlightText text={contentPreview} keyword={highlightKeyword} style={styles.highlight} /> : contentPreview}
+              {highlightKeyword ? <HighlightText text={contentPreview} keyword={highlightKeyword} highlightStyle={styles.highlight} /> : contentPreview}
             </Text>
           </View>
         )}
@@ -676,7 +676,7 @@ const PostCardInner: React.FC<PostCardProps> = (normalizedProps) => {
 
         {!!post.title && (
           <Text style={styles.gridTitleMain} numberOfLines={hasImage ? 2 : 3}>
-            {highlightKeyword ? <HighlightText text={post.title} keyword={highlightKeyword} style={styles.highlight} /> : post.title}
+            {highlightKeyword ? <HighlightText text={post.title} keyword={highlightKeyword} highlightStyle={styles.highlight} /> : post.title}
           </Text>
         )}
 
@@ -748,7 +748,7 @@ const PostCardInner: React.FC<PostCardProps> = (normalizedProps) => {
 
       {!!post.title && (
         <Text style={styles.title} numberOfLines={isCompact ? 2 : undefined}>
-          {highlightKeyword ? <HighlightText text={post.title} keyword={highlightKeyword} style={styles.highlight} /> : post.title}
+          {highlightKeyword ? <HighlightText text={post.title} keyword={highlightKeyword} highlightStyle={styles.highlight} /> : post.title}
         </Text>
       )}
 
@@ -758,7 +758,7 @@ const PostCardInner: React.FC<PostCardProps> = (normalizedProps) => {
             style={styles.content}
             numberOfLines={isExpanded ? undefined : contentNumberOfLines}
           >
-            {highlightKeyword ? <HighlightText text={content} keyword={highlightKeyword} style={styles.highlight} /> : content}
+            {highlightKeyword ? <HighlightText text={content} keyword={highlightKeyword} highlightStyle={styles.highlight} /> : content}
           </Text>
           {shouldTruncate && (
             <TouchableOpacity onPress={() => setIsExpanded((prev) => !prev)} style={styles.expandBtn}>

src/components/business/PostContentRenderer.tsx

@@ -61,7 +61,7 @@ const PostContentRenderer: React.FC<PostContentRendererProps> = ({
     return (
       <Text numberOfLines={numberOfLines} selectable style={textStyle}>
         {highlightKeyword && content ? (
-          <HighlightText text={content} keyword={highlightKeyword} style={highlightStyle} />
+          <HighlightText text={content} keyword={highlightKeyword} highlightStyle={highlightStyle} />
         ) : (
           content || ''
         )}
@@ -85,7 +85,7 @@ const PostContentRenderer: React.FC<PostContentRendererProps> = ({
             elements.push(
               <Text key={key} selectable style={textStyle}>
                 {highlightKeyword ? (
-                  <HighlightText text={text} keyword={highlightKeyword} style={highlightStyle} />
+                  <HighlightText text={text} keyword={highlightKeyword} highlightStyle={highlightStyle} />
                 ) : (
                   text
                 )}
@@ -125,7 +125,7 @@ const PostContentRenderer: React.FC<PostContentRendererProps> = ({
       return (
         <Text numberOfLines={numberOfLines} selectable style={textStyle}>
           {highlightKeyword && content ? (
-            <HighlightText text={content} keyword={highlightKeyword} style={highlightStyle} />
+            <HighlightText text={content} keyword={highlightKeyword} highlightStyle={highlightStyle} />
           ) : (
             content || ''
           )}

src/components/business/UserProfileHeader.tsx

@@ -551,7 +551,6 @@ function createUserProfileHeaderStyles(colors: AppColors) {
       minWidth: 160,
       backgroundColor: colors.background.paper,
       borderRadius: borderRadius.lg,
-      ...shadows.lg,
       borderWidth: StyleSheet.hairlineWidth,
       borderColor: colors.divider,
       overflow: 'hidden',

src/screens/home/HomeScreen.tsx

@@ -364,7 +364,7 @@ export const HomeScreen: React.FC = () => {
   useEffect(() => {
     if (homeTabPressCount > 0) {
       // 滚动 FlashList 到顶部
-      flashListRef.current?.scrollToOffset({ offset: 0, animated: true });
+      flashListRef.current?.scrollToOffset({ offset: 0, animated: false });
       // 滚动 ScrollView 到顶部（网格模式）
       scrollViewRef.current?.scrollTo({ y: 0, animated: true });
       // 重置底部 Tab 栏状态

src/screens/message/components/ChatScreen/styles.ts

@@ -208,11 +208,6 @@ export function createChatScreenStyles(colors: AppColors, dynamicStyles?: {
     backgroundColor: 'rgba(255, 255, 255, 0.96)',
     borderWidth: StyleSheet.hairlineWidth,
     borderColor: 'rgba(0, 0, 0, 0.08)',
-    shadowColor: colors.chat.shadow,
-    shadowOffset: { width: 0, height: 2 },
-    shadowOpacity: 0.12,
-    shadowRadius: 6,
-    elevation: 4,
   },
   jumpToLatestFabText: {
     fontSize: 13,

src/screens/message/components/ChatScreen/useChatScreen.ts

@@ -1104,7 +1104,10 @@ export const useChatScreen = (props?: ChatScreenProps) => {
     setSending(true);
 
     try {
-      const segments: MessageSegment[] = [...buildTextSegments(trimmedText, replyingTo)];
+      // 有文本或回复时才构建文本段，纯图片时不塞空 text
+      const segments: MessageSegment[] = (trimmedText || replyingTo)
+        ? [...buildTextSegments(trimmedText, replyingTo)]
+        : [];
       for (const url of uploadedUrls) {
         segments.push({
           type: 'image',

src/screens/profile/UserScreen.tsx

@@ -24,7 +24,7 @@ export const UserScreen: React.FC = () => {
       <UserProfileScreen
         mode={isSelfProfile ? 'self' : 'other'}
         userId={isSelfProfile ? undefined : userId}
-        hasHeader={false}
+        hasHeader
       />
     </SafeAreaView>
   );