feat(ui): border radius on canvas

Author: psychedelicious

invokeai/frontend/web/src/features/controlLayers/components/StageComponent.tsx

@@ -239,7 +239,7 @@ export const StageComponent = memo(({ asPreview = false }: Props) => {
   return (
     <Flex overflow="hidden" w="full" h="full">
       <Flex ref={wrapperRef} w="full" h="full" alignItems="center" justifyContent="center">
-        <Flex ref={containerRef} tabIndex={-1} bg="base.850" />
+        <Flex ref={containerRef} tabIndex={-1} bg="base.850" borderRadius="base" overflow="hidden" />
       </Flex>
     </Flex>
   );