TEXT nodes created via SceneGraph.createNode() defaulted to empty
fills, causing text to be invisible when .fig files are opened in
Figma. Now defaults to a solid black fill matching Figma's behavior.
Closes#133
Strip optical size suffixes (e.g. "DM Sans 9pt" → "DM Sans") and
"Variable" suffixes when writing fontName.family to .fig files.
This ensures Figma recognizes the font instead of showing a
"Missing font" dialog.
Closes#131