feat(server): trigger workspace embedding (#12328)

fix AI-127

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

- **New Features**
  - Added automated event handling for workspace updates and document embedding, streamlining document embedding workflows.
  - Introduced detection and queuing of documents needing embedding, excluding ignored documents.
- **Improvements**
  - Enhanced performance of embedding-related searches by filtering results at the database level.
  - Increased concurrency for embedding job processing to improve throughput.
- **Bug Fixes**
  - Improved error handling and fallback for missing document titles during embedding.
  - Added safeguards to skip invalid embedding jobs based on document identifiers.
- **Tests**
  - Expanded test coverage for document embedding and ignored document filtering.
  - Updated end-to-end tests to use dynamic content for improved reliability.
  - Added synchronization waits in document creation utilities to improve test stability.
<!-- end of auto-generated comment: release notes by coderabbit.ai -->

packages/backend/server/src/models/workspace.ts

@@ -7,6 +7,7 @@ import { BaseModel } from './base';
 
 declare global {
   interface Events {
+    'workspace.updated': Workspace;
     'workspace.deleted': {
       id: string;
     };
@@ -58,6 +59,9 @@ export class WorkspaceModel extends BaseModel {
     this.logger.debug(
       `Updated workspace ${workspaceId} with data ${JSON.stringify(data)}`
     );
+
+    this.event.emit('workspace.updated', workspace);
+
     return workspace;
   }