Deletion blocked when Knowhere archive returns document not found

[suguanYang]

Summary

Deleting a Notebook source can fail permanently when the local source row still has a knowhereDocumentId, but the upstream Knowhere document has already been deleted or archived.

Observed on staging for source 887294db-a793-4522-9254-45808dfb77d0.

Evidence

Vercel staging log at 2026-07-05 22:29:55 CST:

PATCH /api/sources/887294db-a793-4522-9254-45808dfb77d0 -> 500
knowhere: documents.archive("doc_6dda64c37f74")
knowhere: documents.archive failed: Document not found

The route aborts before the Notebook local row is soft-deleted.

Code Path

src/domains/sources/route-archive.ts archives the Knowhere document before calling sourceService.softDelete(...):

client.documents.archive(source.knowhereDocumentId)
sourceService.softDelete(workspace.id, input.sourceId)

Expected Behavior

If Knowhere returns a not-found response during archive, Notebook should still soft-delete/hide the local source row. Upstream absence means there is nothing left to archive, not that the user-visible row must remain undeletable.

Suggested Fix

Treat Knowhere NotFoundError / 404 from documents.archive as archive success for local deletion purposes. Preserve normal failure behavior for other errors.

Verification

Add a route-service test where documents.archive throws Knowhere not-found and assert the local softDelete still runs and the response is success.