Refine tool call summaries and scrolling (#2069)

* feat(app): refine tool call summaries and scrolling

Keep summary groups stable from the first tool call, preserve live activity feedback, and scroll expanded groups to the latest entry. Consolidate web scrollbar styling around the native browser mechanism.

* refactor(app): reuse tool call height constant

* fix(app): preserve tool call summary state

* fix(app): refresh web tool groups on expand

* fix(app): preserve grouped tool errors

packages/app/src/components/draggable-list.web.tsx

@@ -17,7 +17,6 @@ import {
 } from "@dnd-kit/sortable";
 import { CSS } from "@dnd-kit/utilities";
 import type { DraggableListProps, DraggableRenderItemInfo } from "./draggable-list.types";
-import { useWebScrollViewScrollbar } from "./use-web-scrollbar";
 import { getPointerActivationConstraint, useDragReorderState } from "./drag-reorder";
 
 export type { DraggableListProps, DraggableRenderItemInfo };
@@ -133,7 +132,6 @@ export function DraggableList<T>({
   ListHeaderComponent,
   ListEmptyComponent,
   showsVerticalScrollIndicator = true,
-  enableDesktopWebScrollbar = false,
   scrollEnabled = true,
   extraData: _extraData,
   useDragHandle = false,
@@ -147,11 +145,6 @@ export function DraggableList<T>({
     onDragEnd,
     onDragBegin,
   });
-  const showCustomScrollbar = enableDesktopWebScrollbar && scrollEnabled;
-  const scrollViewRef = useRef<ScrollView>(null);
-  const scrollbar = useWebScrollViewScrollbar(scrollViewRef, {
-    enabled: showCustomScrollbar,
-  });
   const pointerActivationConstraint = getPointerActivationConstraint(
     useDragHandle,
     POINTER_ACTIVATION_CONFIG,
@@ -183,15 +176,10 @@ export function DraggableList<T>({
     <View style={wrapperStyle}>
       {scrollEnabled ? (
         <ScrollView
-          ref={scrollViewRef}
           testID={testID}
           style={style}
           contentContainerStyle={contentContainerStyle}
-          showsVerticalScrollIndicator={showCustomScrollbar ? false : showsVerticalScrollIndicator}
-          onLayout={scrollbar.onLayout}
-          onContentSizeChange={scrollbar.onContentSizeChange}
-          onScroll={scrollbar.onScroll}
-          scrollEventThrottle={16}
+          showsVerticalScrollIndicator={showsVerticalScrollIndicator}
         >
           {ListHeaderComponent}
           {items.length === 0 && ListEmptyComponent}
@@ -254,7 +242,6 @@ export function DraggableList<T>({
           {ListFooterComponent}
         </>
       )}
-      {scrollbar.overlay}
     </View>
   );
 }