REIFY Phase 0.1. Add the end-to-end Phase-0 example: reify a flat enum
(value: i64, closed) from a TypeInfo literal, construct E.value(3) /
E.closed, and match both arms. Seed an empty expected/*.exit marker.
RED by design (reify still bails -> "unparseable expected exit"); the
next commit (0.2) implements reify and turns it green. Satisfies the
no-commit-both-adds-a-test-and-passes cadence.
