Firm→client document delivery

Staff deliver documents TO clients — the reverse of today's request/upload flow. Unblocks returns delivery, e-sign template sends, and title-only sends (V2/F001; market-audit decision #4, ADR-adjacent contract section already Planned in documents.contract.md).

Depends on the S3 + ClamAV pipeline, which is now live-proven (clean + EICAR quarantine drills on prod, 2026-07-05). Wave 1. Feeds Templates slice 2 (engagement letters render → delivered document) and acceptance v2 (signed artifact lands as a delivered document).