Returns metadata for a specific report document and a secure, time-limited
pre-signed URL for downloading the file.

The signed URL expires after the specified number of seconds and must be used
before that time. This endpoint ensures secure access to stored report files
without exposing them publicly.

Response includes:

• id — unique document identifier
• name — human-readable report title
• signed_url — downloadable, pre-signed URL
• expires_in_seconds — time remaining before the URL expires