Pricing

Every book with its current version and the plans pointing at it. The live-subscriber count on each plan is the blast radius of an edit — and the only place a `price_book_id` is discoverable at all.

Every version, newest first, with full contents — enough to diff any two, or to republish an old one as the newest, which is what a rollback is.

Publish the next version. Holds authorized after it commits price against the new version; every hold already open keeps the one it was opened under and settles at that one's prices, so an edit can never reprice work a customer has already started.

The quantities the rater understands and the rate-sheet key each is priced under — a code constant served so the editor's field-level validation cannot drift from the code that does the pricing. It says nothing about which sheet is in force.

Newest first, full tables inline — one call serves the list, a row's detail and the editor's starting point (the row payments marks `in_force`).

Schedule a complete new sheet for a future instant. It is a draft until then: settle cannot see it, and it can still be edited. Only one may be pending at a time.

Edit the draft in place: its instant may move later or earlier while it stays in the future, and moving it alone is a real edit. Once the instant passes the sheet is frozen — settled usage rows point at it — and this answers 409 `RATE_SHEET_IN_FORCE`.