refactor: adopt shared page and workspace layouts

docs/ACCESSIBILITY_REVIEW.md

@@ -1,8 +1,11 @@
 # Campaign Accessibility Review
 
 The Campaign WebUI uses Core's semantic `Button`, `Dialog`, `DataGrid`, form,
-alert, and segmented-control components. Core owns focus trapping, focus return,
-Escape handling, labels, disabled state, and keyboard behavior for those shared
+alert, and segmented-control components. Its page frames use Core `PageLayout`
+and its full-canvas navigation/content shells use `WorkspaceLayout`, so pane
+scrolling, sticky headings, action collapse, narrow-layout behavior, and help
+scope remain platform-owned. Core also owns focus trapping, focus return,
+Escape handling, labels, disabled state, and keyboard behavior for the shared
 primitives.
 
 ## Repeatable review matrix