DocxReader never populates WordDocument.sectionProperties from the body-level <w:sectPr>

[ebolamerican]

Title: DocxReader never populates WordDocument.sectionProperties from the body-level <w:sectPr>

Summary

DocxReader reads and then discards the document-wide <w:sectPr>. WordDocument.sectionProperties is left at its SectionProperties() defaults. Because any typed re-emission of word/document.xml rebuilds <w:sectPr> from that defaulted model, a round-trip that touches the body (insert_paragraph, add_header, …) silently collapses the section to defaults — dropping header/footer references, custom margins, page size/orientation, titlePg, pgNumType, vAlign, line numbers, and docGrid.

Root cause

In DocxReader.swift the body-child switch explicitly skips sectPr:

case "sectPr":
    // <w:sectPr> as a direct child of <w:body> is the document-wide
    // section properties block. It's parsed separately into
    // `WordDocument.sectionProperties` (not into BodyChild) — skip
    // here so it doesn't get captured as a `.rawBlockElement`.
    continue

The comment claims it is "parsed separately into WordDocument.sectionProperties", but there is no such parse — grep -n "sectionProperties =" Sources/OOXMLSwift/IO/DocxReader.swift returns nothing. The block is skipped and never read into the typed model.

Impact

Every source-loaded document that has meaningful section properties (essentially all real-world Word docs — footer references, non-default margins, letter/A4 page size, landscape sections) loses them the first time a typed edit re-emits document.xml. This is a silent data-loss bug.

Repro

1. Open a .docx whose body <w:sectPr> has a <w:footerReference> and custom <w:pgMar>.
2. insert_paragraph (or any typed body edit) and save.
3. Inspect the saved word/document.xml: <w:sectPr> now carries default margins and no footer reference.

Suggested fix

Parse the body-level <w:sectPr> into WordDocument.sectionProperties in DocxReader (header/footer references by type, pgSz, pgMar, cols, titlePg, section break type, pgNumType, vAlign, lnNumType, docGrid), matching the fields the typed model can already represent. Either that, or preserve the raw <w:sectPr> verbatim and re-emit it unchanged when the typed model hasn't modified it.

Workaround in place downstream

che-word-mcp's open_document now hydrates sectionProperties from the source <w:sectPr> itself (hydrateSectionProperties) as a server-side shim. That covers the fields the typed model represents but can't recover sectPr children the model doesn't model (footnotePr, rsid attrs, exotic children) — so a proper reader-side fix is still wanted.

Environment

ooxml-swift v1.4.0.