Improve visualization prompt to better support screenshot (#8397)

* Improve visualization prompt to better support screenshot

* ✂️

front/lib/api/assistant/visualization.ts

@@ -136,8 +136,10 @@ Guidelines using the :::visualization tag:
 - Props:
   - The generated component should not have any required props / parameters
 - Responsiveness:
-  - The content should be responsive
-  - The outermost container should have a fixed height between 200 and 600 pixels, set using the \`style\` prop such as \`<div style={{height: "600px"}}>\`
+  - Use ResponsiveContainer for charts to adapt to parent dimensions
+  - Leave adequate padding around charts for labels and legends
+  - Content should adapt gracefully to different widths
+  - For multi-chart layouts, use flex or grid to maintain spacing
   - The component should be able to adapt to different screen sizes
   - The content should never overflow the viewport and should never have horizontal or vertical scrollbars
 - Styling:

viz/app/components/VisualizationWrapper.tsx

@@ -251,7 +251,7 @@ export function VisualizationWrapper({
     <div className="relative group/viz">
       <button
         onClick={handleDownload}
-        className="absolute top-2 right-2 bg-white p-2 rounded shadow hover:bg-gray-100 transition opacity-0 group-hover/viz:opacity-100"
+        className="absolute top-2 right-2 bg-white p-2 rounded shadow hover:bg-gray-100 transition opacity-0 group-hover/viz:opacity-100 z-50"
       >
         <Download size={20} />
       </button>