fix: CI build errors + fourth-pass perf (IList cast, IDE0004/IDE0032, touch/hit-policy/relax/taiko allocs)

Agent-Logs-Url: https://github.com/winnerspiros/osu/sessions/16daf401-e98b-42e6-8464-4745383d6e40

Co-authored-by: winnerspiros <1675249+winnerspiros@users.noreply.github.com>

Author: Copilot

osu.Game/Rulesets/UI/GameplaySampleTriggerSource.cs

@@ -68,9 +68,9 @@ public virtual void Play()
             if (nextObject == null)
                 return;
 
-            // HitSampleInfo implements ISampleInfo, so array covariance lets us cast without
-            // allocating a second array via .Cast<ISampleInfo>().ToArray().
-            PlaySamples((ISampleInfo[])nextObject.Samples.ToArray());
+            // HitSampleInfo : ISampleInfo (reference type) — array covariance makes the assignment
+            // implicit; no explicit cast or second array allocation needed.
+            PlaySamples(nextObject.Samples.ToArray());
         }
 
         protected virtual void PlaySamples(ISampleInfo[] samples) => Schedule(() =>

osu.Game/Screens/OnlinePlay/Matchmaking/Queue/CloudVisualisation.cs

@@ -23,28 +23,27 @@ namespace osu.Game.Screens.OnlinePlay.Matchmaking.Queue
     /// </summary>
     public partial class CloudVisualisation : CompositeDrawable
     {
-        private APIUser[] users = [];
         private Container usersContainer = null!;
 
         private readonly Bindable<double?> lastSamplePlayback = new Bindable<double?>();
 
         public APIUser[] Users
         {
-            get => users;
+            get;
             set
             {
-                users = value;
+                field = value;
                 if (IsLoaded)
                     refresh();
             }
-        }
+        } = [];
 
         private void refresh()
         {
             foreach (var u in usersContainer)
                 u.Delay(RNG.Next(0, 1000)).FadeOut(500).Expire();
 
-            LoadComponentsAsync(users.Select(u => new MovingAvatar(u, lastSamplePlayback)), avatars =>
+            LoadComponentsAsync(Users.Select(u => new MovingAvatar(u, lastSamplePlayback)), avatars =>
             {
                 if (usersContainer.Count == 0)
                 {

osu.Game/Screens/Select/BeatmapCarouselFilterSorting.cs

@@ -155,7 +155,7 @@ private static int compareUsingAggregateMax(BeatmapInfo a, BeatmapInfo b, Func<B
         /// <paramref name="beatmaps"/>, or <see cref="double.NegativeInfinity"/> if every beatmap
         /// is hidden. Single-pass, allocation-free (no LINQ enumerator).
         /// </summary>
-        private static double aggregateMax(IReadOnlyList<BeatmapInfo> beatmaps, Func<BeatmapInfo, double> func)
+        private static double aggregateMax(IList<BeatmapInfo> beatmaps, Func<BeatmapInfo, double> func)
         {
             double max = double.NegativeInfinity;