feat(ui): support invisible resizable split separators

packages/ui-react/src/SplitPane.tsx

@@ -23,6 +23,7 @@ export interface SplitPaneProps extends Omit<HTMLAttributes<HTMLDivElement>, "ch
   step?: number;
   resizable?: boolean;
   separatorLabel: string;
+  separatorAppearance?: "line" | "invisible";
 }
 
 const clamp = (value: number, minimum: number, maximum: number) => (
@@ -48,6 +49,7 @@ export function SplitPane({
   step = 2,
   resizable = true,
   separatorLabel,
+  separatorAppearance = "line",
   className,
   style,
   ...props
@@ -95,6 +97,7 @@ export function SplitPane({
       ref={rootRef}
       className={cn("nodedc-split-pane", className)}
       data-orientation={orientation}
+      data-separator-appearance={separatorAppearance}
       data-dragging={dragging ? "true" : undefined}
       style={splitStyle}
       {...props}