fix(app): keyboard navigation previous/next message (#15047)

packages/app/src/pages/session.tsx

@@ -254,12 +254,13 @@ export default function Page() {
     const msgs = visibleUserMessages()
     if (msgs.length === 0) return
 
-    const current = activeMessage()
-    const currentIndex = current ? msgs.findIndex((m) => m.id === current.id) : -1
-    const targetIndex = currentIndex === -1 ? (offset > 0 ? 0 : msgs.length - 1) : currentIndex + offset
-    if (targetIndex < 0 || targetIndex >= msgs.length) return
+    const current = store.messageId
+    const base = current ? msgs.findIndex((m) => m.id === current) : msgs.length
+    const currentIndex = base === -1 ? msgs.length : base
+    const targetIndex = currentIndex + offset
+    if (targetIndex < 0 || targetIndex > msgs.length) return
 
-    if (targetIndex === msgs.length - 1) {
+    if (targetIndex === msgs.length) {
       resumeScroll()
       return
     }

packages/app/src/pages/session/message-timeline.tsx

@@ -376,6 +376,7 @@ export function MessageTimeline(props: {
         >
           <Show when={showHeader()}>
             <div
+              data-session-title
               classList={{
                 "sticky top-0 z-30 bg-[linear-gradient(to_bottom,var(--background-stronger)_48px,transparent)]": true,
                 "w-full": true,

packages/app/src/pages/session/use-session-hash-scroll.ts

@@ -45,7 +45,9 @@ export const useSessionHashScroll = (input: {
 
     const a = el.getBoundingClientRect()
     const b = root.getBoundingClientRect()
-    const top = a.top - b.top + root.scrollTop
+    const sticky = root.querySelector("[data-session-title]")
+    const inset = sticky instanceof HTMLElement ? sticky.offsetHeight : 0
+    const top = Math.max(0, a.top - b.top + root.scrollTop - inset)
     root.scrollTo({ top, behavior })
     return true
   }