feat(openapi): add rail + settlement-timing fields to OutgoingTransaction

mintlify/ramps/platform-tools/webhooks.mdx

@@ -37,7 +37,11 @@ Grid sends webhooks for key events in the ramp lifecycle:
       "customerId": "Customer:019542f5-b3e7-1d02-0000-000000000001",
       "settledAt": "2025-10-03T15:02:30Z",
       "exchangeRate": 9.5,
-      "quoteId": "Quote:019542f5-b3e7-1d02-0000-000000000006"
+      "quoteId": "Quote:019542f5-b3e7-1d02-0000-000000000006",
+      "paymentRail": "ACH",
+      "railSelectionMode": "AUTO",
+      "expectedSettlementAt": "2025-10-04T15:00:00Z",
+      "settlementTimelineSeconds": 86400
     }
   }
   ```

openapi/components/schemas/common/RailSelectionMode.yaml

@@ -0,0 +1,8 @@
+type: string
+enum:
+  - AUTO
+  - MANUAL
+description: >-
+  How the payment rail was chosen — MANUAL when the platform specified a
+  paymentRail on the destination, AUTO when Lightspark selects it.
+example: AUTO

openapi/components/schemas/transactions/OutgoingTransaction.yaml

@@ -73,3 +73,37 @@ allOf:
       failureReason:
         $ref: ./OutgoingTransactionFailureReason.yaml
         description: If the transaction failed, this field provides the reason for failure.
+      paymentRail:
+        anyOf:
+          - $ref: ../common/PaymentRail.yaml
+          - type: 'null'
+        description: >-
+          The payment rail used to settle this transaction (e.g. ACH, WIRE,
+          NEFT, FASTER_PAYMENTS). Uses the same values as the PaymentRail sent
+          on quote requests. Null when no external rail is used (e.g. instant
+          or intra-network transfers, or non-direct-destination transactions)
+          or before a rail is resolved.
+      railSelectionMode:
+        anyOf:
+          - $ref: ../common/RailSelectionMode.yaml
+          - type: 'null'
+        description: >-
+          How the rail was chosen — MANUAL when the platform specified a
+          paymentRail on the destination, AUTO when Lightspark selects it. Null
+          when no rail is resolved.
+      expectedSettlementAt:
+        type:
+          - string
+          - 'null'
+        format: date-time
+        description: >-
+          Expected settlement time at the beneficiary. Null for instant rails
+          (settlement is immediate) and before a rail with deferred settlement
+          is resolved.
+      settlementTimelineSeconds:
+        type:
+          - integer
+          - 'null'
+        description: >-
+          Expected number of seconds from quote creation to settlement. Null
+          when not yet known.