fix(story): harden notebook interaction and fallback

app/components/story/notebookTimeline.ts

@@ -81,6 +81,7 @@ function getCursorPoint(
   progress: number,
   phase: NotebookPhase,
   activeTabIndex: number,
+  tabCount: number,
 ): { x: number; y: number } {
   if (phase === "cursor-in") {
     const cursorProgress = (progress - 0.34) / 0.1;
@@ -94,8 +95,19 @@ function getCursorPoint(
     return { x: 0.06, y: 0.88 };
   }
 
-  const point = CURSOR_POINTS[activeTabIndex % CURSOR_POINTS.length];
-  return point;
+  const target = CURSOR_POINTS[activeTabIndex % CURSOR_POINTS.length];
+  if (phase !== "browse" || activeTabIndex === 0) return target;
+
+  const browseProgress =
+    (progress - BROWSE_START) / (BROWSE_END - BROWSE_START);
+  const slotProgress = browseProgress * tabCount - activeTabIndex;
+  const previous = CURSOR_POINTS[(activeTabIndex - 1) % CURSOR_POINTS.length];
+  const moveProgress = clamp(slotProgress / 0.36, 0, 1);
+
+  return {
+    x: interpolate(previous.x, target.x, moveProgress),
+    y: interpolate(previous.y, target.y, moveProgress),
+  };
 }
 
 function isCursorClicking(
@@ -124,7 +136,7 @@ function isCursorClicking(
   const browseProgress =
     (progress - BROWSE_START) / (BROWSE_END - BROWSE_START);
   const slotProgress = (browseProgress * tabCount) % 1;
-  return slotProgress < 0.12;
+  return slotProgress >= 0.36 && slotProgress < 0.5;
 }
 
 export function getNotebookFrame(
@@ -173,6 +185,7 @@ export function getNotebookFrame(
     normalizedProgress,
     phase,
     activeTabIndex,
+    normalizedTabCount,
   );
 
   return {