feat: split individual semantic change (#13155)

<!-- This is an auto-generated comment: release notes by coderabbit.ai
-->
## Summary by CodeRabbit

* **New Features**
* Introduced a new AI-powered document update feature, allowing users to
apply multiple independent block-level edits to Markdown documents.
* Added support for applying document updates via a new GraphQL query,
enabling seamless integration with the frontend.

* **Enhancements**
* Improved the document editing tool to handle and display multiple
simultaneous edit operations with better UI feedback and state
management.
* Expanded model support with new "morph-v3-fast" and "morph-v3-large"
options for document update operations.
* Enhanced frontend components and services to support asynchronous
application and acceptance of multiple document edits independently.

* **Bug Fixes**
* Enhanced error handling and user notifications for failed document
update operations.

* **Documentation**
* Updated tool descriptions and examples to clarify the new multi-edit
workflow and expected input/output formats.
<!-- end of auto-generated comment: release notes by coderabbit.ai -->

> CLOSE AI-337

packages/backend/server/src/plugins/copilot/providers/utils.ts

@@ -472,10 +472,18 @@ export class TextStreamParser {
         result = this.addPrefix(result);
         switch (chunk.toolName) {
           case 'doc_edit': {
-            if (chunk.result && typeof chunk.result === 'object') {
-              result += `\n${chunk.result.result}\n`;
+            if (
+              chunk.result &&
+              typeof chunk.result === 'object' &&
+              Array.isArray(chunk.result.result)
+            ) {
+              result += chunk.result.result
+                .map(item => {
+                  return `\n${item.changedContent}\n`;
+                })
+                .join('');
               this.docEditFootnotes[this.docEditFootnotes.length - 1].result =
-                chunk.result.result;
+                result;
             } else {
               this.docEditFootnotes.pop();
             }