docs: adopt CTO dataset semantics

docs/decisions/0013-payment-lifecycle-and-fee-semantics.md

@@ -7,7 +7,7 @@
 
 The source exposes session states `Paid`, `Verified`, `Failed`, and `Reversed`, but names alone did not establish business meaning. Authoritative clarification from ZarinPal's CTO defines a two-step lifecycle: the buyer first completes payment at the bank, then the merchant calls verification. `Paid` means the bank payment succeeded and funds were deducted but merchant verification is incomplete. `Verified` means both steps completed. `Reversed` is possible but extremely rare; the dataset contains one such session.
 
-The challenge field `adjusted_fee` was transformed/name-adjusted for participant confidentiality, but the product domain treats it as the merchant's real fee. Profiling found its value constant within every session: 150,450 repeated attempt rows and zero fee conflicts.
+The CTO data guide states that challenge `adjusted_fee` is uniformly scaled for commercial confidentiality and is not the actual ZarinPal tariff; relative ordering, trends, and fee share remain valid. The approved product contract nevertheless treats the canonical production field as the merchant's real fee because accepted production data will supply the real value. Profiling found the challenge value constant within every session: 150,450 repeated rows and zero conflicts.
 
 ## Decision
 
@@ -24,7 +24,7 @@ Paid amount is the session amount summed once for (`Paid`, `Verified`). Also exp
 
 A retried session has more than one attempt. An eventually paid retry has final session status `Paid` or `Verified` and at least one lower-`try_seq` attempt whose status is neither `Paid` nor `Verified`; CSV row order is irrelevant.
 
-Rename source `adjusted_fee` to canonical `fee_amount_rial`, store it once on the session, and present it as a real Rial merchant fee. Paid fee totals sum it once for bank-paid sessions. Fee rate is `sum(paid session fee) / sum(paid session amount)` with numerator, denominator, period, and unit visible.
+Map challenge `adjusted_fee` into canonical `fee_amount_rial` for the demo and require production writers to provide the real Rial fee under that canonical contract. Store it once on the session and present the canonical product value as the real merchant fee. Paid fee totals sum it once for bank-paid sessions. Fee rate is `sum(paid session fee) / sum(paid session amount)` with numerator, denominator, period, and unit visible.
 
 ## Consequences