Declared differences: equivalence except where a person approved a difference #4051

What. Declared differences: equivalence except where a person has approved a difference, explicitly.

Byte-for-byte is not always what a customer wants: a defect the port keeps today ("DEFECT KEPT" notes in the ports, e.g. CSUTLDTC's WS-DATE move) may be fixed later; EBCDIC text becomes UTF-8; DB2 becomes Postgres, and collation or timestamp precision changes.

Design:

• a case (or the estate) carries a list of declared differences: which output/field, the rule (e.g. "text re-encoded cp037 -> UTF-8", "field X: the fixed value"), why, and who approved;
• the harness applies them when comparing and reports every place one was used: a difference is never silent;
• the evidence record lists them; an undeclared difference is still a failed proof.

Part of epic #4055 (the product is the proof).

🤖 Generated with Claude Code