feat(Theme): enhance theming and UI consistency across components

- Updated app.json to set userInterfaceStyle to automatic for improved theme adaptability.
- Refactored layout components to utilize useAppColors for dynamic theming, ensuring consistent color usage.
- Introduced SystemChrome component to manage system UI background color based on theme.
- Enhanced TabsLayout, ProfileStackLayout, and other components to leverage new theming structure.
- Improved QRCodeScanner, SearchBar, and CommentItem styles to align with the updated theme system.
- Consolidated styles in SystemMessageItem and TabBar for better maintainability and visual coherence.

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

@@ -546,6 +546,13 @@ export const useChatScreen = () => {
     isBrowsingHistoryRef.current = false;
   }, [isHistoryLoadingLocked]);
 
+  /** 用户点击「回到底部」：解除浏览历史锁并滚到最新消息端（inverted 下 offset=0） */
+  const jumpToLatestMessages = useCallback(() => {
+    suppressAutoFollowRef.current = false;
+    isBrowsingHistoryRef.current = false;
+    scrollToLatest(true, true, 'jump-latest-button');
+  }, [scrollToLatest]);
+
   const setBrowsingHistory = useCallback((browsing: boolean) => {
     isBrowsingHistoryRef.current = browsing;
   }, []);
@@ -1396,6 +1403,7 @@ export const useChatScreen = () => {
     handleClearConversation,
     handleMessageListContentSizeChange,
     handleReachLatestEdge,
+    jumpToLatestMessages,
     setBrowsingHistory,
   };
 };