refactor(core): optimize state management and component rendering performance

Improve application stability and performance by optimizing Zustand store usage, implementing memoization patterns, and introducing persistent authentication.

- **State Management**:
  - Refactor Zustand selectors to use `useShallow` and `getState()` to prevent unnecessary re-renders and infinite loops in hooks.
  - Implement `persist` middleware for `authStore` to maintain user sessions across restarts.
  - Introduce `buildStateCached` in `themeStore` to reduce redundant theme object computations.
- **Performance & Rendering**:
  - Implement `useMemo` for stable object/array references in `ImageGallery` and list components to prevent expensive re-renders.
  - Replace inline arrow functions with `useCallback` in complex screens like `ChatScreen` and `MessageListScreen`.
  - Optimize `FlashList` usage by providing stable `key` and `extraData` props.
- **Architecture**:
  - Decouple unread count fetching by introducing `useUnreadCountQuery` (React Query) for better caching and synchronization.
  - Add `useChannels` hook to centralize channel data fetching.
  - Refine `SessionGate` logic to allow immediate rendering of authenticated users while verifying in the background.

src/screens/message/MessageListScreen.tsx

@@ -152,6 +152,11 @@ export const MessageListScreen: React.FC = () => {
   // 系统通知显示状态 - 用于在移动端显示通知页面
   const [showNotifications, setShowNotifications] = useState(false);
 
+  // Stable callbacks to avoid inline arrows passed to child components
+  const stableCloseNotifications = useCallback(() => setShowNotifications(false), []);
+  const stableClearSelectedConversation = useCallback(() => setSelectedConversation(null), []);
+  const stableCloseScanner = useCallback(() => setScannerVisible(false), []);
+
   // 系统消息会话对象（用于选中状态）
   const systemMessageConversation: ConversationResponse = useMemo(() => ({
     id: SYSTEM_MESSAGE_CHANNEL_ID,
@@ -197,14 +202,11 @@ export const MessageListScreen: React.FC = () => {
     return FLOATING_TAB_BAR_HEIGHT + insets.bottom + spacing.md;
   }, [isWideScreen, insets.bottom]);
 
-  // 【新架构】页面获得焦点时初始化MessageManager
+  // 初始化MessageManager（仅首次），焦点时轻量刷新会话列表
   useEffect(() => {
-    if (isFocused) {
-      messageManager.initialize();
-    }
-  }, [isFocused]);
+    messageManager.initialize();
+  }, []);
 
-  // 【新架构】使用focus刷新hook，从ChatScreen返回时自动刷新未读数
   useMessageListRefresh();
 
   // 同步未读数到userStore（用于TabBar角标显示）
@@ -840,7 +842,7 @@ export const MessageListScreen: React.FC = () => {
           <View style={styles.chatArea}>
             {showNotifications ? (
               // 显示系统通知页面
-              <NotificationsScreen onBack={() => setShowNotifications(false)} />
+              <NotificationsScreen onBack={stableCloseNotifications} />
             ) : selectedConversation ? (
               // 显示选中会话的聊天内容
               <ChatScreen
@@ -849,7 +851,7 @@ export const MessageListScreen: React.FC = () => {
                 embeddedIsGroupChat={selectedConversation.type === 'group'}
                 embeddedGroupId={selectedConversation.group ? String(selectedConversation.group.id) : undefined}
                 embeddedGroupName={selectedConversation.group?.name}
-                onEmbeddedBack={() => setSelectedConversation(null)}
+                onEmbeddedBack={stableClearSelectedConversation}
               />
             ) : (
               // 默认占位符
@@ -871,7 +873,7 @@ export const MessageListScreen: React.FC = () => {
     <SafeAreaView style={styles.container} edges={['top', 'bottom']}>
       {showNotifications ? (
         // 显示系统通知页面，传入 onBack 回调
-        <NotificationsScreen onBack={() => setShowNotifications(false)} />
+        <NotificationsScreen onBack={stableCloseNotifications} />
       ) : isSearchMode ? (
         renderSearchMode()
       ) : isWideScreen ? (
@@ -882,7 +884,7 @@ export const MessageListScreen: React.FC = () => {
         renderConversationList()
       )}
       {renderActionMenu()}
-      <QRCodeScanner visible={scannerVisible} onClose={() => setScannerVisible(false)} />
+      <QRCodeScanner visible={scannerVisible} onClose={stableCloseScanner} />
     </SafeAreaView>
   );
 };