Markdown of a single page (page is 0-indexed).
An out-of-range page comes back as a placeholder with empty markdown
and needs_ocr: true (upstream behaviour, not an error).
Summary
Types
@type t() :: %PdfInspector.PageMarkdown{ markdown: String.t(), needs_ocr: boolean(), ocr_reason: String.t() | nil, page: non_neg_integer() }