Fix shared canvas override wiping on close

Author: Av1ralS1ngh

src/components/Flow.tsx

@@ -2299,7 +2299,10 @@ function FlowContent() {
             onStartEmpty={handleWelcomeStartEmpty}
             onLoadExample={handleWelcomeLoadExample}
             hideStartEmpty={isMobileReadOnly}
-            onOpenChange={setShowWelcomeDialog}
+            onOpenChange={(open) => {
+              setShowWelcomeDialog(open);
+              if (!open) markWelcomeComplete();
+            }}
           />
         </div>
       </FlowActionsProvider>

src/components/dialog/FirstRunDialog.tsx

@@ -79,17 +79,7 @@ export function FirstRunDialog({
   };
 
   const handleOpenChange = (nextOpen: boolean) => {
-    if (nextOpen) {
-      onOpenChange?.(true);
-      return;
-    }
-    if (actionRef.current === null && !hideStartEmpty) {
-      actionRef.current = "empty";
-      onStartEmpty();
-      onOpenChange?.(false);
-      return;
-    }
-    onOpenChange?.(false);
+    onOpenChange?.(nextOpen);
   };
 
   const dialogDescription = hideStartEmpty