v0.0.68

Added

• Image transform DSL: presets can be layered by listing multiple names (hero,square), with trailing literal overrides winning (hero,square,w=800). Presets can reference other presets; circular references throw.

Changed

• PageFiles::resolveOptions() is the single entry point for expanding an option string, presets first, then literals. PageImage::resolveVariant() and srcset() both use it instead of their own inline preset-vs-literal branching.