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/schema.gql

@@ -1518,6 +1518,9 @@ type PublicUserType {
 type Query {
   """get the whole app configuration"""
   appConfig: JSONObject!
+
+  """Apply updates to a doc using LLM and return the merged markdown."""
+  applyDocUpdates(docId: String!, op: String!, updates: String!, workspaceId: String!): String!
   collectAllBlobSizes: WorkspaceBlobSizes! @deprecated(reason: "use `user.quotaUsage` instead")
 
   """Get current user"""