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

backend/contracts/sendico/models/account/account.yaml

@@ -0,0 +1,15 @@
+components:
+  schemas:
+    AccountData:
+      description: Extended account payload including visibility-specific metadata.
+      allOf:
+        - $ref: ./account_public.yaml#/components/schemas/AccountPublic
+        - type: object
+          description: Account attributes that are not part of the public profile.
+          additionalProperties: false
+          required:
+            - isAnonymous
+          properties:
+            isAnonymous:
+              description: Indicates whether the account is marked as anonymous.
+              type: boolean