Suppress paragraph space-before at the top of a new page

[JSv4]

Summary

Docxodus paints a paragraph's w:spacing/@w:before when that paragraph begins a new page, placing page-top headings about 15 px lower than Microsoft Word.

This residual was isolated in the legal-contract case while adding Microsoft Graph Word-reference captures in PR #423. It is separate from the list-number suffix-tab bug completed in #415.

Reproduction

Render TestFiles/VP/VP004-Legal-Contract.docx in paginated mode at 96 DPI and compare the first visible heading/content on pages 2 and 3.

Evidence

Page	Microsoft Graph first ink row	LibreOffice first ink row	Docxodus first ink row
2	100 px	99 px	115 px
3	100 px	99 px	115 px

Both independent office renderers suppress the heading's space-before at the top of these pages. Docxodus retains approximately 15 px.

For the three-page fixture, Docxodus-versus-Word measured mean SSIM 0.69031 and worst ink F1 0.51261; LibreOffice-versus-Word measured mean SSIM 0.93049 and worst ink F1 0.99737. The exact first-ink rows isolate this defect from font differences and the other content on the pages.

Expected

When this paragraph is laid out at the top of a new page, its space-before should be suppressed as Word does.

Actual

Docxodus applies the space-before as a visible top offset after pagination.

Acceptance criteria

• Add a minimal generated DOCX regression with a spaced-before paragraph beginning a new page.
• Cover the relevant break mechanisms present in the fixture (and document which mechanism controls suppression).
• Assert page-top geometry independently of font glyph shapes.
• Suppress only the Word-equivalent page-top spacing; preserve ordinary inter-paragraph spacing.
• Rerun the tracked legal-contract visual-parity case and record the improvement.

Provenance

Microsoft Graph conversion reference: Microsoft Graph v1.0 DOCX-to-PDF conversion, rasterized at 96 DPI. The reproducible capture and measurement metadata are being added by PR #423; no Word artifact needs to be committed.