From the M1 review (no correctness bugs found; these are accuracy corrections to
shipped artifacts, not new feature work):
- migration gate: the `v1 == migrated` assertion's comment overclaimed a
universal inverse. It is round-trip self-consistency over the representative
corpus (which is built from the same valuegen helpers the migration
reconstructs values with); the spec-level property is the reduction-equivalence
asserted alongside it. The ReplaceWithRest rest-voice is the known
non-invertible field, recovered from the deleted event's placement at reduction.
- operation_catalog §CreateCrossCutting: document that v0→v1 migration covers the
event-anchored Tie/Slur/Beam; a Spanner (anchor-based) cannot be reconstructed
from the v0 event-reference and is reported unmigratable (read-only) under M1,
so the catalog no longer silently implies it round-trips.
Review findings deferred to M2 (per project lead): migrate.rs unit tests for the
untested reconstruction branches, and the valuegen::spelling() mod-7 domain
cleanup. Gates unchanged and green (comment + spec-text only).
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>