feat(server): cleanup trashed doc's embedding (#13201)

fix AI-359

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

* **New Features**
* Added automated cleanup of embeddings for documents deleted or trashed
from workspaces.
* Introduced a new job to schedule and perform this cleanup per
workspace daily and on demand.
  * Added new GraphQL mutation to manually trigger the cleanup process.
* Added the ability to list workspaces with flexible filtering and
selection options.

* **Improvements**
* Enhanced document status handling to more accurately reflect embedding
presence.
* Refined internal methods for managing and checking document
embeddings.
<!-- end of auto-generated comment: release notes by coderabbit.ai -->

packages/backend/server/src/__tests__/models/copilot-context.spec.ts

@@ -164,11 +164,14 @@ test('should insert embedding by doc id', async t => {
     );
 
     {
-      const ret = await t.context.copilotContext.hasWorkspaceEmbedding(
+      const ret = await t.context.copilotContext.listWorkspaceEmbedding(
         workspace.id,
         [docId]
       );
-      t.true(ret.has(docId), 'should return doc id when embedding is inserted');
+      t.true(
+        ret.includes(docId),
+        'should return doc id when embedding is inserted'
+      );
     }
 
     {
@@ -317,8 +320,8 @@ test('should merge doc status correctly', async t => {
 
     const hasEmbeddingStub = Sinon.stub(
       t.context.copilotContext,
-      'hasWorkspaceEmbedding'
-    ).resolves(new Set<string>());
+      'listWorkspaceEmbedding'
+    ).resolves([]);
 
     const stubResult = await t.context.copilotContext.mergeDocStatus(
       workspace.id,