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/server/src/collaboration/collaboration.util.ts

@@ -41,7 +41,8 @@ import { generateHTML, generateJSON } from '../common/helpers/prosemirror/html';
 // see: https://github.com/ueberdosis/tiptap/issues/5352
 // see:https://github.com/ueberdosis/tiptap/issues/4089
 //import { generateJSON } from '@tiptap/html';
-import { Node } from '@tiptap/pm/model';
+import { Node, Schema } from '@tiptap/pm/model';
+import { Logger } from '@nestjs/common';
 
 export const tiptapExtensions = [
   StarterKit.configure({
@@ -110,9 +111,53 @@ export function jsonToText(tiptapJson: JSONContent) {
 }
 
 export function jsonToNode(tiptapJson: JSONContent) {
-  return Node.fromJSON(getSchema(tiptapExtensions), tiptapJson);
+  const schema = getSchema(tiptapExtensions);
+  try {
+    return Node.fromJSON(schema, tiptapJson);
+  } catch (error) {
+    if (
+      error instanceof RangeError &&
+      error.message.includes('Unknown node type')
+    ) {
+      Logger.warn('Stripping unknown node types from document:', error.message);
+      const cleanedJson = stripUnknownNodes(tiptapJson, schema);
+      return Node.fromJSON(schema, cleanedJson);
+    }
+    throw error;
+  }
 }
 
 export function getPageId(documentName: string) {
   return documentName.split('.')[1];
 }
+
+function stripUnknownNodes(
+  json: JSONContent,
+  schema: Schema,
+): JSONContent | null {
+  if (!json || typeof json !== 'object') return json;
+
+  // Recursively clean children first, flattening any unwrapped content
+  if (json.content && Array.isArray(json.content)) {
+    const newContent: JSONContent[] = [];
+    for (const child of json.content) {
+      const cleaned = stripUnknownNodes(child, schema);
+      if (Array.isArray(cleaned)) {
+        newContent.push(...cleaned);
+      } else if (cleaned) {
+        newContent.push(cleaned);
+      }
+    }
+    json.content = newContent;
+  }
+
+  // Check if this node is unknown AFTER processing children
+  if (json.type && !schema.nodes[json.type]) {
+    // Unwrap: return cleaned children directly instead of wrapping
+    return (
+      json.content && json.content.length > 0 ? json.content : null
+    ) as any;
+  }
+
+  return json;
+}