fix: address Copilot review comments

- Update comment to be more accurate about content jumping prevention
- Use userName computed property consistently in AuthorInfoView
- Restore scroll-based title bar animation with List using PreferenceKey

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <[email protected]>

Author: graycreate

V2er/View/FeedDetail/AuthorInfoView.swift

@@ -85,7 +85,7 @@ struct AuthorInfoView: View {
         .background(
             Group {
                 NavigationLink(destination: TagDetailPage(tag: tag, tagId: tagId), isActive: $navigateToTag) { EmptyView() }
-                NavigationLink(destination: UserDetailPage(userId: data?.userName ?? .empty), isActive: $navigateToUser) { EmptyView() }
+                NavigationLink(destination: UserDetailPage(userId: userName), isActive: $navigateToUser) { EmptyView() }
             }
             .hidden()
         )

V2er/View/FeedDetail/FeedDetailPage.swift

@@ -9,6 +9,13 @@
 import SwiftUI
 import SafariServices
 
+private struct ScrollOffsetPreferenceKey: PreferenceKey {
+    static var defaultValue: CGFloat = 0
+    static func reduce(value: inout CGFloat, nextValue: () -> CGFloat) {
+        value = nextValue()
+    }
+}
+
 struct FeedDetailPage: StateView, KeyboardReadable, InstanceIdentifiable {
     @Environment(\.isPresented) private var isPresented
     @Environment(\.dismiss) var dismiss
@@ -107,6 +114,14 @@ struct FeedDetailPage: StateView, KeyboardReadable, InstanceIdentifiable {
                 .listRowInsets(EdgeInsets())
                 .listRowSeparator(.hidden)
                 .listRowBackground(Color.itemBg)
+                .background(
+                    GeometryReader { geometry in
+                        Color.clear.preference(
+                            key: ScrollOffsetPreferenceKey.self,
+                            value: geometry.frame(in: .named("listScroll")).minY
+                        )
+                    }
+                )
 
             // Content Section
             if !isContentEmpty {
@@ -166,6 +181,12 @@ struct FeedDetailPage: StateView, KeyboardReadable, InstanceIdentifiable {
         .onTapGesture {
             replyIsFocused = false
         }
+        .coordinateSpace(name: "listScroll")
+        .onPreferenceChange(ScrollOffsetPreferenceKey.self) { offset in
+            withAnimation {
+                hideTitleViews = offset > -100
+            }
+        }
     }
 
     private var replyBar: some View {

V2er/View/Widget/Updatable/UpdatableView.swift

@@ -112,7 +112,7 @@ struct UpdatableView<Content: View>: View {
     private func onScroll(point: CGPoint) {
         let newScrollY = point.y
 
-        // Detect bottom overscroll - skip state updates to prevent LazyVStack jumping
+        // Detect bottom overscroll - skip state updates to prevent content jumping during bottom overscroll
         let isBottomOverscroll = boundsDelta > 0 && newScrollY < -boundsDelta - 5
         if isBottomOverscroll {
             lastScrollY = newScrollY