Records what was built against the plan (names are encrypted from v1, rights
for other people are folder-scoped S3 keys), how to run pithos-hosted, and
that paid storage belongs to Hestia, a separate product.
One s3d serves one Sia account, so hosting means one s3d per user on the
server. Writing down the agreed model (bring your own sia.storage account,
client-side encryption except public files, BNS-name-or-deposit gate), how
the gateway enforces per-folder rights s3d cannot, and how a data folder
moves between PC and server without re-uploading to Sia, before building.
