Remove platform tenancy from SXCHNGE customer BFF (#34)

README.md

@@ -146,6 +146,7 @@ usability, accessibility and journey measurement under the repository's UX rules
 
 The integration is: **consumer app → sxchnge BFF → Sendico public HTTP API**.
 SXCHNGE is one organization in Sendico; its customers are owned locally.
+Local accounts have no organization tenancy, membership, roles or policy engine.
 
 - sxchnge will own consumer registration/sessions, onboarding and exchange UX,
   and mappings from local customers to organization-scoped platform resources.