Field names are lower snake_case
Data-model field names are lower snake_case: lowercase words joined by
underscores (current_balance, borrower_id). No camelCase, no
PascalCase, no hyphens at the data-model layer. UI component names and
TypeScript type names are out of this rule's scope.
Evidence
Every field in CE_C05's entity tables (borrower_id, ssn_hash, citizenship_status, …) and every Known/Envelope property in the POC's protocol.ts follows lower snake_case or lowerCamel; the engineering SOT set is uniformly snake_case at the data-model layer.