fix(app): stabilize session timeline layout continuity (#34533)

packages/app/src/pages/session.tsx

@@ -26,6 +26,7 @@ import { FileProvider, selectionFromLines, useFile, type FileSelection, type Sel
 import { createStore } from "solid-js/store"
 import { ResizeHandle } from "@opencode-ai/ui/resize-handle"
 import { Select } from "@opencode-ai/ui/select"
+import { isScrollKeyTarget, scrollKey, scrollKeyOwner } from "@opencode-ai/ui/scroll-view"
 import { Tabs } from "@opencode-ai/ui/tabs"
 import { ButtonV2 } from "@opencode-ai/ui/v2/button-v2"
 import { createAutoScroll } from "@opencode-ai/ui/hooks"
@@ -940,9 +941,11 @@ export default function Page() {
       if (id && shouldFocusTerminalOnKeyDown(event) && focusTerminalById(id)) return
     }
 
-    // Only treat explicit scroll keys as potential "user scroll" gestures.
-    if (event.key === "PageUp" || event.key === "PageDown" || event.key === "Home" || event.key === "End") {
-      markScrollGesture()
+    const key = scrollKey(event)
+    if (key) {
+      if (!scroller || !isScrollKeyTarget(target ?? null, key)) return
+      if (scrollKeyOwner(scroller, target ?? null, key) !== scroller) return
+      markScrollGesture(scroller)
       return
     }