No behaviour change: every command keeps its id, label, menu, shortcut and
params doc.
- Engine: swatch.* -> cmd/swatch.rs, graphicStyle.* -> cmd/style.rs,
appearance.* (incl. copyFrom) -> cmd/appearance.rs, stroke.set/setAdvanced
-> cmd/stroke.rs, paint.editGradient/setGradientGeom -> cmd/gradient.rs.
Shared helpers in cmd/mod.rs: leaf_targets/paint_targets (replacing three
copies) and unique_name (swatch and graphic style naming).
- UI: dialogs.rs -> dialogs/ with one file per dialog and a DialogSpec
registry (one DialogKind row per dialog); shared field widgets in
dialogs/form.rs. Headless frame tests draw and confirm every dialog.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
