19-task implementation plan layering on top of Wave 11.B. Builds three system-managed roots (Clients/Companies/Yachts), per-entity auto- subfolders, Documenso auto-deposit on completion, owner-aggregated projection (symmetric reach, file-FK source of truth, defense-in-depth port_id), and the hub UI rebuild. Hard cutover; backfill via idempotent script. Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>