# Independent transfer — PageSettings

This fixture has no pre-solved mapper. It is deliberately not an isomorphic rename of RequestPayload: it contains a `theme` literal union, a nested `layout` record, and a `tags` string array. Implement `mapper.ts` independently, then run `bash run_checks.sh`.

Your transfer evidence must preserve the lesson's success contract:
- trust boundary and why the value starts uncertain;
- runtime checks for the literal union, nested layout fields, and every tags element;
- narrowing before typed use;
- compile-time evidence;
- malformed-input behavior;
- one **claim boundary**;
- one **update condition** stating what schema/config/compiler change would make you re-run the evidence.

Do not copy the RequestPayload guard line by line; reconstruct the method for the different control-flow and shape.