[Features] Get document content by ID or name within a collection

[earayu]

We need a way to directly retrieve the content of a specific document using its collection_id and document_id (or document_name).

To implement this, we could:

1. Create a new, dedicated HTTP endpoint (and/or MCP endpoint).
2. Or, extend the existing /api/v1/collections/{collection_id}/searches interface to handle this specific lookup.

[github-actions]

This issue has been marked as stale because it has been open for 30 days with no activity