feat(message): add conversation notification mute feature

Add notification mute functionality for conversations with the following changes:

- Add notification_muted field to ConversationResponse and related DTOs
- Add notificationMutedMap to message store for tracking mute state
- Add setConversationNotificationMuted API method
- Integrate mute toggle in GroupInfoScreen and PrivateChatInfoScreen
- Skip system notifications for muted conversations
- Suppress vibration for muted conversations in WS handler
- Clean up selected mentions when @mentions are removed from text

Chore changes:
- Update PostCard bookmark icon from 'bookmark' to 'star'
- Refine card styles across AppsScreen, MaterialsScreen, and SubjectMaterialsScreen
- Improve week selector scrolling to center selected week in ScheduleScreen

src/components/business/PostCard/PostCard.tsx

@@ -721,7 +721,7 @@ const PostCardInner: React.FC<PostCardProps> = (normalizedProps) => {
           </TouchableOpacity>
           <TouchableOpacity style={styles.actionBtn} onPress={handleBookmark}>
             <MaterialCommunityIcons
-              name={post.is_favorited ? 'bookmark' : 'bookmark-outline'}
+              name={post.is_favorited ? 'star' : 'star-outline'}
               size={18}
               color={post.is_favorited ? colors.warning.main : colors.text.secondary}
             />