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

backend/contracts/sendico/models/auth/client_refresh_token.yaml

@@ -0,0 +1,15 @@
+components:
+  schemas:
+    ClientRefreshToken:
+      description: Refresh token bound to a specific client and device session.
+      allOf:
+        - $ref: ./session_identifier.yaml#/components/schemas/SessionIdentifier
+        - type: object
+          description: Refresh-token payload associated with the session identifier.
+          additionalProperties: false
+          required:
+            - token
+          properties:
+            token:
+              description: Long-lived token used to obtain a new access token.
+              type: string