perf: memoize EditorCanvas to prevent unnecessary re-renders

src/client/components/EditorCanvas.tsx

@@ -1,3 +1,4 @@
+import { memo } from "react";
 import "../../../node_modules/@excalidraw/excalidraw/dist/prod/index.css";
 import { Excalidraw } from "@excalidraw/excalidraw";
 import type {
@@ -33,7 +34,9 @@ function sceneFromEditor(
   };
 }
 
-export function EditorCanvas({
+// ⚡ Bolt: Wrapped in React.memo to prevent expensive Excalidraw re-renders
+// when parent state (like the sidebar open state or drawing title input) changes.
+export const EditorCanvas = memo(function EditorCanvas({
   activeId,
   scene,
   loading,
@@ -58,4 +61,4 @@ export function EditorCanvas({
       />
     </div>
   );
-}
+});