fix(ui): scroll-shadow bottom fade + hide tasks row when nothing active

- ScrollShadow: 1px subpixel tolerance so bottom fade clears at scroll end
  on Retina (fractional scrollTop was keeping data-bottom-scroll stuck)
- StatusRow: hide tasks indicator when no in-progress/pending todos remain

packages/ui/src/components/chat/StatusRow.tsx

@@ -200,7 +200,7 @@ export const StatusRow: React.FC<StatusRowProps> = ({
     return { active, left };
   }, [visibleTodos]);
 
-  const hasTodoContent = showTodos && visibleTodos.length > 0;
+  const hasTodoContent = showTodos && statusSummary.left > 0;
   const hasAssistantContent = showAssistantStatus && (
     isWorking ||
     Boolean(wasAborted) ||

packages/ui/src/components/ui/ScrollShadow.tsx

@@ -89,11 +89,18 @@ export const ScrollShadow = React.forwardRef<HTMLElement, ScrollShadowProps>(
         return;
       }
 
-      const hasBefore = orientation === "vertical" ? el.scrollTop > offset : el.scrollLeft > offset;
+      // Subpixel tolerance: on hi-DPI (Retina) and with fractional scrollTop,
+      // scrollTop+clientHeight can fall ~0.5px short of scrollHeight at the very end,
+      // which would otherwise keep the bottom fade visible after fully scrolling.
+      const SUBPIXEL_TOLERANCE = 1;
+      const hasBefore =
+        orientation === "vertical"
+          ? el.scrollTop > offset + SUBPIXEL_TOLERANCE
+          : el.scrollLeft > offset + SUBPIXEL_TOLERANCE;
       let hasAfter =
         orientation === "vertical"
-          ? el.scrollTop + el.clientHeight + offset < el.scrollHeight
-          : el.scrollLeft + el.clientWidth + offset < el.scrollWidth;
+          ? el.scrollHeight - (el.scrollTop + el.clientHeight) > offset + SUBPIXEL_TOLERANCE
+          : el.scrollWidth - (el.scrollLeft + el.clientWidth) > offset + SUBPIXEL_TOLERANCE;
 
       const effectiveHasBefore = hideTopShadow && orientation === "vertical" ? false : hasBefore;