feat(layers): implement row context menu and actions

- Add right-click context menu on layer, group, and object rows:
  - Options... / Layer Options... / Options for Selection...
  - Duplicate <name> / Duplicate Selection
  - Delete <name> / Delete Selection
  - Lock Others / Unlock All Layers
  - Hide Others / Show All Layers
  - Locate Object
  - Collect for Export
- Select unselected row on right-click; preserve multiselection if already highlighted
- Dispatch actions via registered engine commands with Undo/Redo tracking
- Add headless egui tests covering selection, dispatch, and state integrity
- Update gaps and ui-parity documentation for G12

docs/ui-parity.md

@@ -51,6 +51,7 @@ Artboard Options forwards the active Artboard tool's Scale Artwork with Artboard
 
 | Date | Change | Summary |
 |---|---|---|
+| 2026-11-14 | minor | Layers panel: right-clicking a layer/group/object row shows a context menu with Options…, Duplicate, Delete, Lock/Hide Others, Locate Object, and Collect for Export — matching standard desktop layer panel conventions. Scores unchanged. |
 | 2026-11-13 | minor | Swatches: in a panel made taller the swatch list fills the space above the footer instead of scrolling inside 150 or 200 pt (#1638). Scores unchanged. |
 | 2026-11-08 | minor | Style panels: a double-click on a user character style's row opens its Character Style Options (`ui.charStyleOptions`), and on a paragraph style's row its Paragraph Style Options (rename); the Character Style Options dialog keeps a fixed width and scrolls its sections in a shorter window, so OK and Cancel stay on screen. Tests `panels::text_styles::tests::double_clicking_a_character_style_row_opens_its_options` and `dialogs::char_style_options::tests::the_sections_scroll_in_a_window_shorter_than_the_general_list`. Scores and estimates unchanged. |
 | 2026-11-08 | minor | #3380, deletion only: preserve gradient placement and exact surviving geometry; consume owned subpaths with a shared original-node snapshot; consolidate status/evidence and document command/helper contracts. Compound behavior and the existing M2 status entry are retained. Endpoint highlighting remains open; scores and estimates unchanged. |
@@ -430,7 +431,8 @@ next unit in the order a right-click on a ruler lists them, from Feet back to Po
 | Pathfinder panel › Pathfinder Options…: Precision, Remove Redundant Points, Divide and Outline Will Remove Unpainted Artwork | done | #3426; `object.pathfinder.options`, kept in the preferences; defaults (0.01 pt, both off) keep the earlier results; [spec](https://helpx.adobe.com/illustrator/desktop/manage-objects/reshape-transform-objects/pathfinder-panel-overview.html) |
 | Cmd/Ctrl+4 repeats the last successful Shape Mode or Pathfinder operation on the selection | done | Panel operations, direct `object.pathfinder.*` commands and `command.batch` steps (Actions playback) set history; `action.batch`, Trap, compound-shape edits and live effects do not. Repeat uses current Pathfinder Options; [key spec](https://web.archive.org/web/20260726060015/https://helpx.adobe.com/illustrator/using/default-keyboard-shortcuts.html), [menu spec](https://helpx.adobe.com/illustrator/desktop/manage-objects/reshape-transform-objects/pathfinder-panel-overview.html) |
 | Pathfinder panel: compound shapes (Make, Release and Expand Compound Shape in the panel menu, Alt-click a Shape Mode, a Shape Mode for selected members, the Expand button) | partial | #4522; `object.compoundShape.make`/`setMode`/`release`/`expand`; members stay editable, the area draws, exports and saves; the button of the members' shared mode is lit; blends, envelopes and warped objects are members as they draw; [spec](https://helpx.adobe.com/illustrator/desktop/manage-objects/reshape-transform-objects/create-compound-shapes-with-pathfinder.html); missing: question marks for mixed modes, hit-testing by the area |
-| Canvas context menu | done | Layers rows, panels and type have none (gap) |
+| Canvas context menu | done | Panels and type have none (gap) |
+| Layers panel row context menu | done | Right-clicking a layer/group/object row shows a context menu with Options…, Duplicate, Delete, Lock/Hide Others, Locate Object, and Collect for Export — matching standard desktop layer panel conventions. |
 | SVG Interactivity panel: JavaScript for each object's events and the document's linked JavaScript files, written to SVG and read back as text | done | `svgInteractivity.*`, `ui.javascriptFilesDialog` |
 | Retype, Comments, Version History panels | missing | the last two are cloud features (out of scope) |
 | Blend panel (30.7) | partial | Window › Blend provides Type (Ease In, Ease Out, Ease In Out, Ease Out In), Ramp 0–100% and independent color Shift, alongside the existing blend controls. Easing is disabled without a spine. Original polynomial distributions approximate the publicly documented behavior; on-canvas easing handles remain missing. [Public source](https://helpx.adobe.com/illustrator/desktop/manage-colors/apply-transparency-and-blending/blend-panel-overview.html) |