Canvas · Panels: layers, inspector, alignment, assets, style and layout editors

LayerPanel lists the canvas's layers topmost first on lists::Tree: a box
shows or hides each, F2 renames, a drag restacks into a new paint order.
InspectorPanel edits the one selected shape's frame, fill, visibility and
lock. AlignmentToolbar lines up or spreads the selection through
`aligned`. AssetPanel finds shapes by name in a picks grid, each drawn
to fit its tile. ColorPanel, ShadowEditor, BorderEditor and
TypographyPanel edit a look; GradientPanel is forms::GradientEditor.
ConstraintsEditor pins a shape to its frame, with `Constraints::placed`;
AutoLayoutControls sets flow, gap, padding and a place grid, with
`AutoLayout::laid`; ExportPanel names each file once. The panels share
`canvas::panel`: editing, pair, caption, heading and color_well.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

tasks/ch31-43.md

@@ -56,18 +56,18 @@
 
 ## T32c Canvas · Panels
 
-- [ ] LayerPanel
-- [ ] AssetPanel
-- [ ] InspectorPanel
-- [ ] AlignmentToolbar
-- [ ] ColorPanel
-- [ ] GradientPanel → `forms::GradientEditor`
-- [ ] ShadowEditor
-- [ ] BorderEditor
-- [ ] TypographyPanel
-- [ ] ConstraintsEditor
-- [ ] AutoLayoutControls
-- [ ] ExportPanel
+- [x] LayerPanel
+- [x] AssetPanel
+- [x] InspectorPanel
+- [x] AlignmentToolbar
+- [x] ColorPanel
+- [x] GradientPanel → `forms::GradientEditor`
+- [x] ShadowEditor
+- [x] BorderEditor
+- [x] TypographyPanel
+- [x] ConstraintsEditor
+- [x] AutoLayoutControls
+- [x] ExportPanel
 
 ## T32d Canvas · Graphs and boards