feat(export): add metadata file to preserve page icons and ordering on import (#1877)

* feat(export): add metadata file to preserve page icons and ordering on import
- Export includes `docmost-metadata.json`
- Import reads metadata to restore icons and sort siblings by original position

* cleanup

* bonus fixes

* handle unknown prosemirror nodes

* add docmost app  version

apps/client/src/features/page/components/page-import-modal.tsx

@@ -172,6 +172,10 @@ function ImportFormatSelection({ spaceId, onClose }: ImportFormatSelection) {
             queryKey: ["root-sidebar-pages", fileTask.spaceId],
           });
 
+          await queryClient.invalidateQueries({
+            queryKey: ["recent-changes", fileTask.spaceId],
+          });
+
           setTimeout(() => {
             emit({
               operation: "refetchRootTreeNodeEvent",