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/adaptive-modal-sheet.tsx

@@ -22,7 +22,6 @@ import {
 import { getCompactSheetSafeAreaPadding } from "@/components/adaptive-modal-sheet-layout";
 import { createControlGeometry } from "@/components/ui/control-geometry";
 import { isNative, isWeb } from "@/constants/platform";
-import { useWebScrollViewScrollbar } from "@/components/use-web-scrollbar";
 import { useSafeAreaInsets } from "react-native-safe-area-context";
 
 // Horizontal indent token shared by the sheet header (title, back arrow,
@@ -460,11 +459,6 @@ export interface AdaptiveModalSheetProps {
   desktopMaxWidth?: number;
   scrollable?: boolean;
   presentation?: "push" | "replace";
-  /**
-   * Render the themed desktop-web scrollbar over the scroll area instead of the
-   * native browser scrollbar. No-op on native and on the mobile bottom sheet.
-   */
-  webScrollbar?: boolean;
 }
 
 export function AdaptiveModalSheet({
@@ -479,16 +473,11 @@ export function AdaptiveModalSheet({
   desktopMaxWidth,
   scrollable = true,
   presentation,
-  webScrollbar = false,
 }: AdaptiveModalSheetProps) {
   const { theme } = useUnistyles();
   const { t } = useTranslation();
   const isMobile = useIsCompactFormFactor();
   const insets = useSafeAreaInsets();
-  const desktopScrollRef = useRef<ScrollView>(null);
-  const desktopScrollbar = useWebScrollViewScrollbar(desktopScrollRef, {
-    enabled: webScrollbar && !isMobile,
-  });
   const resolvedSnapPoints = useMemo(() => snapPoints ?? ["65%", "90%"], [snapPoints]);
   const compactSafeAreaPadding = useMemo(
     () =>
@@ -651,19 +640,13 @@ export function AdaptiveModalSheet({
       {scrollable ? (
         <View style={styles.desktopScrollContainer}>
           <ScrollView
-            ref={desktopScrollRef}
             style={styles.desktopScroll}
             contentContainerStyle={styles.desktopContent}
             keyboardShouldPersistTaps="handled"
-            onLayout={desktopScrollbar.onLayout}
-            onScroll={desktopScrollbar.onScroll}
-            onContentSizeChange={desktopScrollbar.onContentSizeChange}
-            scrollEventThrottle={16}
-            showsVerticalScrollIndicator={!webScrollbar}
+            showsVerticalScrollIndicator
           >
             {children}
           </ScrollView>
-          {desktopScrollbar.overlay}
         </View>
       ) : (
         <View style={styles.desktopStaticContent}>{children}</View>