Reuses a reference TySh block from a PS-generated PSD as a template and
mutates its engine data (Text/FontSize/FillColor/FontSet/transform) per
ppl text layer. Rasterized pixels are kept as channel data so the layer
always displays, and Photoshop treats it as an editable text layer.
Font PostScript names are read from the font files via fontTools.
Verified: 54 TypeLayers, psd_tools reads correct text/engine data.
