DOCX: paragraphs without pStyle skip the default paragraph style

[developer0hye]

Problem

A DOCX paragraph with no explicit w:pStyle should inherit the document's default paragraph style (normally the style marked w:default="1"). office2pdf instead falls back directly to its synthetic document-default text style, whose paragraph properties are empty.

In the public footer regression fixture, the default Normal style supplies paragraph spacing and line spacing. Current main drops those values, visibly compressing the page body upward even though the footer-specific fix itself is correct.

Expected behavior

Apply the full cascade in order: document defaults → default paragraph style → explicit paragraph style → direct paragraph/run formatting. Preserve the default style's spacing, line spacing, size, and other paragraph properties for paragraphs without w:pStyle.

Related: #195, #204, #251

Side-by-side (GT left, office2pdf right)

[developer0hye]

Fixed by PR #315 (merged).

Paragraphs without w:pStyle now inherit the w:default="1" paragraph style: it is folded into the document-default cascade entry, so its spacing, line spacing, and text properties survive the full chain (document defaults → default style → explicit style → direct formatting).

Upstream fork fix: developer0hye/docx-rs@e483367 reads and writes the style default attribute, which the library previously dropped.

Verified on the FancyFoot fixture — paragraph gaps track Word GT instead of collapsing (see the PR's GT/before/after). The residual few-percent tightness is Latin single-spacing line-height parity, tracked under the audit umbrellas.