* M9: visible digital signatures can show a drawn, typed or image graphic (#193)
A visible certificate signature can show a graphic where the signer's
name is large, as Acrobat's Configure Signature Appearance does: the
saved Fill & Sign signature (drawn, typed or image) or an imported
PNG/JPEG. Sign as previews it and remembers the choice; sign_document
takes `graphic` (image, text or strokes).
pdfcraft-sign gains `Graphic` and `SignOptions::graphic`. Graphics are
checked and size-capped before drawing; images keep alpha as a soft
mask and are encrypted with the rest of the update in encrypted files.
Refs #193
* Refresh catalog hashes
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Co-authored-by: Brandon Thomas <[email protected]>