fix: populate fileUrl for knowledge base documents on load

[code-xpertai]

Summary

Fixes #448 - Abnormal image path in knowledge base retrieval results

Problem

When knowledge base documents are created from uploaded files, the fileUrl field is not populated. This causes images to fail rendering in the knowledge base search results.

Root Cause

The KnowledgeDocumentSubscriber had an afterLoad hook that attempted to populate fileUrl from StorageFile, but:

1. It used findOneBy which was deprecated (changed to findOne with where clause)
2. It tried to access storageFile.fileUrl which doesn't exist on StorageFile entity (the entity has file and storageProvider fields, and fileUrl is computed dynamically in StorageFileSubscriber.afterLoad)

Solution

Updated the afterLoad hook in KnowledgeDocumentSubscriber to:

1. Use findOne with proper where clause and select to only fetch needed fields
2. Compute fileUrl directly using FileStorage API (same approach as StorageFileSubscriber)

Changes

• Modified packages/server-ai/src/knowledge-document/document.subscriber.ts
  • Fixed beforeInsert to use findOne instead of deprecated findOneBy
  • Fixed afterLoad to properly compute fileUrl from StorageFile.file and StorageFile.storageProvider

Testing

The fix ensures that when a KnowledgeDocument entity is loaded from the database:

1. If it has a storageFileId but no fileUrl
2. The subscriber fetches the related StorageFile record
3. Computes the full URL using the storage provider
4. Populates entity.fileUrl with the correct URL

This matches the behavior of StorageFileSubscriber.afterLoad which already handles this for StorageFile entities.

[ponyfly6]

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