M4.59: pattern strokes and freeform gradients keep their look in PDF

Pattern strokes are written as the pattern's tiles clipped to the stroke's
outline (dashes, caps, profile, arrowheads and alignment included) instead
of mid-grey; freeform gradients on fills, strokes and type as an image of
their colour field at the document raster effects resolution, clipped to
what they paint, instead of their average colour. Both read back within
2% of the canvas at 150 ppi with no warning. Text strokes are covered for
cap, miter limit, dash array and alignment; knockout groups keep their
soft-masked form with a warning. The freeform box and grid sampling are
shared with the renderer.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

docs/mcp.md

@@ -193,6 +193,9 @@ PDF files take the Save PDF dialog's options: `preset`, `standard`, `compatibili
 `compression`, `marks`, `bleed`, `output`, `advanced` and `security` sections (`list_commands` with filter `exportPdf`
 documents every field). `document.exportPdf` and `export` (format `pdf`, the options in `options`) return `warnings`:
 options accepted but not applied yet, and features approximated or left out. PDF/X, passwords and PDF/A-2b at 2.0 are refused.
+Pattern fills and strokes are written as their tiles clipped to the area they paint (a stroke's outline, with its
+dashes, caps, profile, arrowheads and alignment), and freeform gradients as an image of their colour field at the
+document's raster effects resolution, clipped the same way.
 `document.pdfSettings` lists the options that differ from the preset and the warnings without writing a file.
 
 Opening a PDF (or `.ai`) imports every page as an artboard and layer; `document.open` takes `pages` ("2-3, 5", 1-based),