feat: enhance playground UI

Refine the Playground's UI to improve user experience:

- Streamline chat window layout for better message readability
- Introduce a knowledge selection dropdown for easier context setting
- Improve image upload integration for a smoother workflow
- Optimize spacing and styling for a more polished visual appearance

src/components/Common/CodeBlock.tsx

@@ -90,7 +90,11 @@ export const CodeBlock: FC<Props> = ({ language, value }) => {
           width="80%"
           zIndex={999999}
           centered
-          bodyStyle={{ padding: 0 }}>
+          styles={{
+            body: {
+              padding: 0
+            }
+          }}>
           <div className="relative  w-full h-[80vh]">
             <iframe
               srcDoc={value}