fix(app): keep stream controls clickable under scroll button

The full-width animated overlay won browser hit testing even outside the circular control. Keep positioning on a pass-through container and animate only the button-sized child.

packages/app/e2e/agent-stream-ui.spec.ts

@@ -8,6 +8,7 @@ import {
 } from "./helpers/agent-stream";
 import {
   expectScrollStaysFixed,
+  clickToolCallBesideScrollToBottomButton,
   readScrollMetrics,
   scrollAgentChatToBottom,
   scrollChatAwayFromBottom,
@@ -205,6 +206,37 @@ test.describe("Agent stream UI", () => {
     await expectScrollStaysFixed(page, baseline);
   });
 
+  test("keeps tool calls clickable beside the scroll-to-bottom button", async ({ page }) => {
+    test.setTimeout(60_000);
+    const agent = await seedMockAgentWorkspace({
+      repoPrefix: "stream-scroll-button-hit-area-",
+      title: "Scroll button hit area",
+      model: "ten-second-stream",
+      initialPrompt: "Stream enough content to exercise the scroll button hit area.",
+    });
+    try {
+      await agent.client.waitForFinish(agent.agentId, 30_000);
+      await openAgentRoute(page, {
+        workspaceId: agent.workspaceId,
+        agentId: agent.agentId,
+      });
+      await waitForScrollableChat(page, {
+        minScrollableDistance: SCROLL_AWAY_MIN_SCROLLABLE_DISTANCE,
+        timeout: 30_000,
+      });
+
+      const hitArea = await clickToolCallBesideScrollToBottomButton(page);
+
+      expect(hitArea).toEqual({
+        outsideButton: true,
+        toolCallReceivesPointer: true,
+        withinButtonBand: true,
+      });
+    } finally {
+      await agent.cleanup();
+    }
+  });
+
   test("working-indicator transitions to copy-button when stream ends", async ({ page }) => {
     test.setTimeout(60_000);
     const agent = await startRunningMockAgent(page, {

packages/app/e2e/helpers/agent-bottom-anchor.ts

@@ -124,6 +124,57 @@ export async function scrollChatAwayFromBottom(
   return readScrollMetrics(page);
 }
 
+export async function clickToolCallBesideScrollToBottomButton(page: Page): Promise<{
+  outsideButton: boolean;
+  toolCallReceivesPointer: boolean;
+  withinButtonBand: boolean;
+}> {
+  await scrollChatAwayFromBottom(page, {
+    deltaY: -900,
+    minDistanceFromBottom: 300,
+  });
+
+  const scrollToBottomButton = page.getByRole("button", { name: "Scroll to bottom" });
+  await expect(scrollToBottomButton).toBeVisible();
+
+  const hitArea = await page.evaluate(() => {
+    const button = document.querySelector('[data-testid="scroll-to-bottom-button"]');
+    if (!(button instanceof HTMLElement)) {
+      throw new Error("Expected visible scroll-to-bottom button");
+    }
+    const buttonBounds = button.getBoundingClientRect();
+    const toolCall = Array.from(
+      document.querySelectorAll<HTMLElement>('[data-testid="tool-call-badge"] [role="button"]'),
+    ).find((element) => {
+      const bounds = element.getBoundingClientRect();
+      const centerY = bounds.top + bounds.height / 2;
+      return bounds.width > 0 && centerY >= buttonBounds.top && centerY <= buttonBounds.bottom;
+    });
+    if (!toolCall) {
+      throw new Error("Expected a tool call beside the scroll-to-bottom button");
+    }
+
+    const toolCallBounds = toolCall.getBoundingClientRect();
+    const clickPoint = {
+      x: toolCallBounds.left + 24,
+      y: toolCallBounds.top + toolCallBounds.height / 2,
+    };
+    const hit = document.elementFromPoint(clickPoint.x, clickPoint.y);
+    return {
+      clickPoint,
+      outsideButton: clickPoint.x < buttonBounds.left || clickPoint.x > buttonBounds.right,
+      toolCallReceivesPointer: hit !== null && toolCall.contains(hit),
+      withinButtonBand: clickPoint.y >= buttonBounds.top && clickPoint.y <= buttonBounds.bottom,
+    };
+  });
+  await page.mouse.click(hitArea.clickPoint.x, hitArea.clickPoint.y);
+  return {
+    outsideButton: hitArea.outsideButton,
+    toolCallReceivesPointer: hitArea.toolCallReceivesPointer,
+    withinButtonBand: hitArea.withinButtonBand,
+  };
+}
+
 export async function expectScrollStaysFixed(
   page: Page,
   baseline: ScrollMetrics,

packages/app/src/agent-stream/view.tsx

@@ -905,12 +905,8 @@ const AgentStreamViewComponent = forwardRef<AgentStreamViewHandle, AgentStreamVi
             })}
           </MessageOuterSpacingProvider>
           {!isNearBottom && (
-            <Animated.View
-              style={stylesheet.scrollToBottomContainer}
-              entering={scrollIndicatorFadeIn}
-              exiting={scrollIndicatorFadeOut}
-            >
-              <View style={stylesheet.scrollToBottomInner}>
+            <View style={stylesheet.scrollToBottomContainer} pointerEvents="box-none">
+              <Animated.View entering={scrollIndicatorFadeIn} exiting={scrollIndicatorFadeOut}>
                 <Pressable
                   style={stylesheet.scrollToBottomButton}
                   onPress={scrollToBottom}
@@ -920,8 +916,8 @@ const AgentStreamViewComponent = forwardRef<AgentStreamViewHandle, AgentStreamVi
                 >
                   <ChevronDown size={24} color={stylesheet.scrollToBottomIcon.color} />
                 </Pressable>
-              </View>
-            </Animated.View>
+              </Animated.View>
+            </View>
           )}
         </View>
       </ToolCallSheetProvider>
@@ -1393,13 +1389,6 @@ const stylesheet = StyleSheet.create((theme) => ({
     left: 0,
     right: 0,
     alignItems: "center",
-    pointerEvents: "box-none",
-  },
-  scrollToBottomInner: {
-    width: "100%",
-    maxWidth: MAX_CONTENT_WIDTH,
-    alignSelf: "center",
-    alignItems: "center",
   },
   scrollToBottomButton: {
     width: 48,