feat(studio): groups, a layers panel, marquee, nudge, multi-resize, align and paste style

Elements can be grouped on a page and picked, moved, resized, aligned and
restacked as one. A layers panel lists the page front to back with lock,
visibility, rename and drag to restack. The sheet gains marquee selection,
arrow-key nudge, one box that resizes a multi-selection with Shift holding
the proportions, and the design-tool shortcuts. The inspector lines a
selection up and spaces it out, and copies and pastes a style.

The assistant gets the same through the group, ungroup, name and hide
operations, and describe_book_page lists the groups. The format gains the
optional group, name and hidden fields and a spread's group names, so
BOOK_SCHEMA_REV goes to 2.

client/scripts/rtl-baseline.json

@@ -53,7 +53,7 @@
   "components/Studio/PageNumbers.tsx": 1,
   "components/Studio/PeerCursors.tsx": 1,
   "components/Studio/SpreadView.tsx": 8,
-  "components/Studio/StudioCanvas.tsx": 22,
+  "components/Studio/StudioCanvas.tsx": 12,
   "components/Studio/StudioElementsPanel.tsx": 1,
   "components/Studio/StudioExport.tsx": 1,
   "components/Studio/StudioInspector.tsx": 1,

client/scripts/rtl-disable-baseline.json

@@ -1,4 +1,5 @@
 {
-  "pages/tripPlanner/PlanMapStage.tsx": 4,
-  "mobile/components/trek3d/MascotClip.tsx": 1
+  "components/Studio/StudioSelectionChrome.tsx": 2,
+  "mobile/components/trek3d/MascotClip.tsx": 1,
+  "pages/tripPlanner/PlanMapStage.tsx": 4
 }

client/scripts/strict-baseline.json

@@ -82,7 +82,6 @@
   "src/components/Settings/NotificationsTab.test.tsx": 1,
   "src/components/Settings/PasskeysSection.tsx": 1,
   "src/components/Settings/PhotoProvidersSection.test.tsx": 2,
-  "src/components/Studio/StudioCanvas.tsx": 1,
   "src/components/Studio/StudioInspector.tsx": 1,
   "src/components/Todo/todoListModel.ts": 1,
   "src/components/Tours/planner/TourPlannerPanels.tsx": 2,