Add canvas clear service boundary

docs/modernization/roadmap.md

@@ -514,8 +514,9 @@ draw/erase mode switching also consume the same app-core command planner before
 legacy canvas mode execution continues.
 `pano_cli plan-canvas-clear` exposes app-core planning for the main toolbar
 clear-current-layer command, including clear color validation, no-canvas
-handling, undo recording intent, and dirty-state intent before legacy
-`Canvas::clear` execution continues.
+handling, undo recording intent, and dirty-state intent; live toolbar execution
+now dispatches through `DocumentCanvasClearServices` before the legacy
+`Canvas::clear` adapter continues.
 `pano_cli plan-image-import` exposes app-core planning for File > Import image
 route decisions, including wide equirectangular images, legacy vertical cube
 strips, regular transform-placement images, and invalid image dimensions before
@@ -1235,7 +1236,8 @@ Results:
   toolbar active-state refresh as JSON automation.
 - `pp_app_core_document_canvas_tests` passed, covering clear-current-layer
   undo/dirty intent, no-canvas no-op behavior, and invalid clear color
-  rejection.
+  rejection, service dispatch color forwarding, no-op execution preservation,
+  and invalid execution color rejection.
 - `pano_cli_plan_canvas_clear_smoke`,
   `pano_cli_plan_canvas_clear_no_canvas_smoke`, and
   `pano_cli_plan_canvas_clear_rejects_bad_color` passed and expose toolbar