Bootstrap copied BFF and local accounts with public Sendico contracts (#34)

backend/contracts/sendico/api/payments/fx_currencies.yaml

@@ -0,0 +1,40 @@
+get:
+  tags: [Payments]
+  summary: List available FX currencies
+  description: |
+    Returns the BFF startup-cached Treasury Currency Catalog projection for
+    client-visible FX currencies. `decimals`, `scale`, and `displayScale` are
+    presentation fields backed by Treasury `display_scale`.
+    `accountingScaleCandidate` is informational only and must not be used by
+    clients to determine executable payout precision, quote precision, or
+    guaranteed provider support.
+    The endpoint is authenticated and authorized by `organizations_ref`, but the
+    returned catalogue is global rather than organization-customized. If Treasury
+    was unavailable at BFF startup while this endpoint was enabled, BFF fails
+    startup; if Treasury becomes unavailable after startup, BFF continues serving
+    the cached catalog revision.
+  operationId: paymentsFXCurrencies
+  security:
+    - bearerAuth: []
+  parameters:
+    - $ref: ../parameters/organizations_ref.yaml#/components/parameters/OrganizationsRef
+  responses:
+    '200':
+      description: FX currency catalogue projected from Treasury
+      content:
+        application/json:
+          schema:
+            allOf:
+              - $ref: ../response/response.yaml#/components/schemas/BaseResponse
+              - type: object
+                properties:
+                  data:
+                    $ref: ./response/payment.yaml#/components/schemas/FXCurrenciesData
+    '400':
+      $ref: ../response/operation.yaml#/components/responses/BadRequest
+    '401':
+      $ref: ../response/operation.yaml#/components/responses/Unauthorized
+    '403':
+      $ref: ../response/operation.yaml#/components/responses/Forbidden
+    '503':
+      $ref: ../response/operation.yaml#/components/responses/ServiceUnavailable