// segment: a stretch of textbook prose.
//
// Contract fields:
//   content: `textbook` (required)
//   scalar:  none
//
// Rendered identically for all targets (textbook is always public). Not boxed
// or numbered — it is the connective body text of the lesson.

/// Render a segment part. `show-textbook` is always true in MVP but kept for
/// symmetry with the other kinds' show/hide flags.
#let display-segment(part, show-textbook: true) = {
  if show-textbook {
    part.textbook
  }
}