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>