Fix song select navigation with home/end keys (#36879)

It's a continuation of https://github.com/ppy/osu/pull/36293, but for
the home and end keys.

Now when using home or end keys, it selects respectively the first or
last item in the carousel, instead of just scrolling.

## Before: 


https://github.com/user-attachments/assets/6ab08d2f-1da4-4740-9d9e-574d7a8a10c9

## After:


https://github.com/user-attachments/assets/30bab836-0006-4830-b4e9-2d85017a15e6

osu.Game/Graphics/Carousel/Carousel.ScrollContainer.cs

@@ -9,6 +9,7 @@ using osu.Framework.Graphics;
 using osu.Framework.Graphics.Containers;
 using osu.Framework.Graphics.Cursor;
 using osu.Framework.Graphics.Shapes;
+using osu.Framework.Input;
 using osu.Framework.Input.Bindings;
 using osu.Framework.Input.Events;
 using osu.Framework.Utils;
@@ -31,10 +32,12 @@ namespace osu.Game.Graphics.Carousel
         /// Implementation of scroll container which handles very large vertical lists by internally using <c>double</c> precision
         /// for pre-display Y values.
         /// </summary>
-        protected partial class ScrollContainer : UserTrackingScrollContainer, IKeyBindingHandler<GlobalAction>
+        protected partial class ScrollContainer : UserTrackingScrollContainer, IKeyBindingHandler<GlobalAction>, IKeyBindingHandler<PlatformAction>
         {
             public Action? OnPageUp { get; init; }
             public Action? OnPageDown { get; init; }
+            public Action? OnListStart { get; init; }
+            public Action? OnListEnd { get; init; }
 
             public readonly Container Panels;
 
@@ -146,6 +149,25 @@ namespace osu.Game.Graphics.Carousel
                 return base.OnKeyDown(e);
             }
 
+            public new bool OnPressed(KeyBindingPressEvent<PlatformAction> e)
+            {
+                if (IsHandlingKeyboardScrolling)
+                {
+                    switch (e.Action)
+                    {
+                        case PlatformAction.MoveBackwardLine:
+                            OnListStart?.Invoke();
+                            return true;
+
+                        case PlatformAction.MoveForwardLine:
+                            OnListEnd?.Invoke();
+                            return true;
+                    }
+                }
+
+                return base.OnPressed(e);
+            }
+
             public bool OnPressed(KeyBindingPressEvent<GlobalAction> e)
             {
                 switch (e.Action)

osu.Game/Graphics/Carousel/Carousel.cs

@@ -319,6 +319,8 @@ namespace osu.Game.Graphics.Carousel
                 RelativeSizeAxes = Axes.Both,
                 OnPageUp = () => Scheduler.AddOnce(traverseFromKey, new TraversalOperation(TraversalType.Page, -1)),
                 OnPageDown = () => Scheduler.AddOnce(traverseFromKey, new TraversalOperation(TraversalType.Page, 1)),
+                OnListStart = () => Scheduler.AddOnce(traverseFromKey, new TraversalOperation(TraversalType.Edge, -1)),
+                OnListEnd = () => Scheduler.AddOnce(traverseFromKey, new TraversalOperation(TraversalType.Edge, 1)),
             };
 
             Items.BindCollectionChanged((_, args) =>
@@ -554,6 +556,10 @@ namespace osu.Game.Graphics.Carousel
                     traverseKeyboardPage(traversal.Direction);
                     break;
 
+                case TraversalType.Edge:
+                    traverseKeyboardEdge(traversal.Direction);
+                    break;
+
                 case TraversalType.Set:
                     traverseSetSelection(traversal.Direction);
                     break;
@@ -572,6 +578,7 @@ namespace osu.Game.Graphics.Carousel
             Keyboard,
             Set,
             Page,
+            Edge,
             Group
         }
 
@@ -682,6 +689,27 @@ namespace osu.Game.Graphics.Carousel
             }
         }
 
+        /// <summary>
+        /// Select the first or last item in the carousel.
+        /// </summary>
+        /// <param name="direction">Positive for last item, negative for first item.</param>
+        private void traverseKeyboardEdge(int direction)
+        {
+            if (carouselItems == null || carouselItems.Count == 0)
+                return;
+
+            var item = direction > 0
+                ? carouselItems.LastOrDefault(x => x.IsVisible)
+                : carouselItems.FirstOrDefault(x => x.IsVisible);
+
+            if (item != null && !CheckModelEquality(item.Model, currentKeyboardSelection.Model))
+            {
+                setKeyboardSelection(item.Model);
+                ScrollToSelection();
+                playTraversalSound();
+            }
+        }
+
         /// <summary>
         /// Select the next valid group selection relative to a current selection.
         /// This is generally for keyboard based traversal.