Zenith 0.0.14

Added

• zenith schema write, zenith tx --help, and the starter output list duplicate_node and duplicate_page. The schema write rules also say to check many pages in one call with zenith render --contact-sheet. Before, agents retyped each copy of a repeated row or page and looked at every page on its own. In a 3-brief build run they used duplicate_node and duplicate_page where they used neither before.
• zenith tx --apply --png OUT renders the edited document in the same call. An edit and a look at it are one step instead of two. --page N picks the page (default 1). The page renders before anything is written, so a page that does not render (tx.png_failed) leaves the document and the PNG as they were. A rejected edit writes neither file. --png may not name the document or the tx file, and its directory must exist, as for zenith render --png. If the PNG cannot be written after the edit, the result says the edit is written. The result adds a png object (path, width, height, page, pages) or a png_error string to --json, always as one object.
• content.placeholder warns about sample text left in a document. A text or shape node with role="placeholder", or a span that is exactly the fill-command text <new text>, still holds sample content. zenith validate and zenith tx give one document-level warning that names the first six node ids and a count. It has no subject, so allow "content.placeholder" silences it. The text ops of tx (set_span_text, replace_text, find_replace_text) clear the mark on any node whose text they change, even when only part of the text changed. Other ops and other roles keep it. role holds one value, so a node that needs another role cannot also carry the mark. Every text node of every zenith new --starter layout carries the mark. In the benchmark, two runs delivered a starter with its sample text in place (1 of 7 and 1 of 17 required strings).

Full diff: v0.0.13...v0.0.14