feat: Implement layout persistence for card positions and rotation, loading from and saving to the database.

frontend/src/desktop/DesktopWorkspace.tsx

@@ -54,6 +54,8 @@ export interface DesktopWorkspaceProps {
   onDocumentActivate?: (doc: DeskDocument, event?: unknown) => void;
   onSelectionChange?: (selectedIds: Identifier[]) => void;
   onDocumentTagDrop?: (docId: Identifier, tag: any) => void;
+  tenantId?: Identifier | null;
+  viewId?: string | null;
 }
 
 // Wrapper to handle hooks per card
@@ -84,6 +86,8 @@ const DesktopWorkspace: React.FC<DesktopWorkspaceProps> = ({
   onDocumentActivate,
   onSelectionChange,
   onDocumentTagDrop,
+  tenantId,
+  viewId,
 }) => {
   const containerRef = useRef<HTMLDivElement>(null);
 
@@ -99,6 +103,12 @@ const DesktopWorkspace: React.FC<DesktopWorkspaceProps> = ({
   const layoutStore = useMemo(() => new LayoutStore(), []);
   const layoutRef = useRef<Map<string, LayoutCard>>(new Map());
 
+  useEffect(() => {
+    if (tenantId && viewId) {
+      layoutStore.loadLayout(String(tenantId), viewId);
+    }
+  }, [layoutStore, tenantId, viewId]);
+
   // Selection Context
   const {
     selectedDocumentIds,