Delete Measurement

Soft-delete the measurement and return the soft-deleted row.

Returns 200 with the measurement (deleted_at is set) instead of the REST-idiomatic 204 No Content. The Next.js 16 dev proxy mangles 204 into 503, which would fire useDeleteMeasurement.onError and roll back the client's optimistic remove — producing a "zombie" cache state where the row is gone server-side but present client-side. Subsequent PATCHes on the zombie return 404 and the broad onError rollback would wipe out concurrent drag optimistic writes. Returning 200 with a body avoids the proxy quirk entirely and keeps the FE / BE in sync. Per ADR-0033.