Cash-out and the treasury.

The outward rail is a small addition rather than a new system because four seams already exist. The signed house_post admits a negative delta (proven by the seed debit); create_order pins a rate snapshot at creation and never re-reads the live rate; the players.locked_diamonds column is live, and balance/1 already reports available_diamonds as diamonds − locked_diamonds; and the WHK schema is the designed-forward idempotency shape for a push rail. A hold window is a locked_diamonds move — the column exists; only the policy is new.

def balance(player) do
  case Repo.get(Player, player) do
    nil ->
      nil

    p ->
      p
      |> Map.from_struct()
      |> Map.drop([:__meta__])
      |> Map.merge(%{available_keys: p.keys,
                    available_diamonds: p.diamonds - p.locked_diamonds}) # the hold seam
  end
end

The signed primitive is C6.1: house_post/5 books a signed delta, so the withdrawal debit needs no new verb. This dive is the outward direction the design points at but has not built.

The withdrawal runs five stages. Select one to see the shipped seam it rests on and the forward policy it adds — only the middle stages are new; the endpoints are the same signed ledger and the same rail set the KeyShop uses.

The regulatory and fraud weight is quarantined into cm.8 on purpose: the inward rails ship safely without it, and the outward rail cannot ship without it. Three additions, all forward, each expressed over a shipped seam.

• A rates table with a poller. The floating quote, pinned per withdrawal at request time — the create_order snapshot discipline, inverted for the outward direction. forward
• KYC/AML and the 21-day hold. The compliance gate the outward direction requires, expressed over the shipped locked_diamonds seam — a hold locks diamonds, so available_diamonds falls while the balance does not. forward
• Treasury reconciliation. The platform’s on-chain balances reconciled against the signed revenue_ledger debits — the ledger is the book of record, the chain the counterparty. forward

The design’s rule holds: transparent margin levers, never undisclosed house players. The outward rail is the last piece of the money story — the house’s book (C6.1) and the pay-in (C6.2) are shipped; the withdrawal is where the platform’s obligations to a regulator begin, so it waits for its own rung.