DR-094 — Proving a data-shape invariant requires rows written under the new code

Retired/tombstoned S504. Re-homed (S504 register sweep, owner-ruled S503 merge): testing doctrine belongs in the canonical test-standards home per DR-088. Substance home: canonical:docs/reference/testing/test-philosophy.md (data-shape invariants). Original ADR text retained below; this id stays on disk so citations resolve and the number is never re-issued. An invariant over written data is proven by producing rows under the new code and asserting on those — not by asserting that existing rows are unchanged. Established when the {127.38} pre-state could not be explained: the live rows already held the target value, so an “unchanged” assertion would have passed against code that produced the wrong value.