Fix bitmap memory leaks, load concurrency, money clamp

Bitmap disposal (6 files):
- SlotModel.SetImage: dispose old Avalonia Bitmap + input SKBitmap
- PKMEditorVM: dispose old SpriteImage, LegalityImage, BallSprite
  and intermediate SKBitmaps on every update
- SAVEditorVM: dispose old BoxWallpaper + SKBitmap on box navigation
- WondercardVM: dispose old GiftSlotModel.Sprite on refresh
- QRDialogVM: dispose intermediate SKBitmaps during QR generation
- Added ToAvaloniaBitmapAndDispose helper for owned SKBitmap conversion

Concurrency:
- MainWindowVM: add _isLoading guard to prevent concurrent LoadFileAsync
  calls from drag-drop or rapid Open clicks

Money clamp:
- Trainer8/8a/8b/9/9a: clamp Money to sav.MaxMoney on save
  (was allowing values exceeding game maximums)

PKHeX.Avalonia/Controls/SlotModel.cs

@@ -64,7 +64,10 @@ public partial class SlotModel : ObservableObject
 
     public void SetImage(SKBitmap? skBitmap)
     {
+        var old = Image;
         Image = SKBitmapToAvaloniaBitmapConverter.ToAvaloniaBitmap(skBitmap);
+        old?.Dispose();
+        skBitmap?.Dispose();
         IsEmpty = skBitmap is null;
     }
 }

PKHeX.Avalonia/Converters/SKBitmapToAvaloniaBitmapConverter.cs

@@ -46,4 +46,22 @@ public class SKBitmapToAvaloniaBitmapConverter : IValueConverter
         stream.Position = 0;
         return new Bitmap(stream);
     }
+
+    /// <summary>
+    /// Converts an SKBitmap to an Avalonia Bitmap and disposes the input SKBitmap.
+    /// Use this when the caller owns the SKBitmap and will not reuse it after conversion.
+    /// </summary>
+    public static Bitmap? ToAvaloniaBitmapAndDispose(SKBitmap? skBitmap)
+    {
+        if (skBitmap is null)
+            return null;
+        try
+        {
+            return ToAvaloniaBitmap(skBitmap);
+        }
+        finally
+        {
+            skBitmap.Dispose();
+        }
+    }
 }

PKHeX.Avalonia/ViewModels/MainWindowViewModel.cs

@@ -27,6 +27,11 @@ public partial class MainWindowViewModel : ObservableObject
 {
     private readonly IDialogService _dialogService;
 
+    /// <summary>
+    /// Guards against concurrent invocations of <see cref="LoadFileAsync"/>.
+    /// </summary>
+    private bool _isLoading;
+
     /// <summary>
     /// The file path from which the current save file was loaded.
     /// Used to create an automatic backup before overwriting.
@@ -345,6 +350,9 @@ private async Task DumpAllBoxesAsync()
 
     public async Task LoadFileAsync(string path)
     {
+        if (_isLoading)
+            return;
+        _isLoading = true;
         try
         {
             var data = await File.ReadAllBytesAsync(path);
@@ -370,6 +378,10 @@ public async Task LoadFileAsync(string path)
         {
             await _dialogService.ShowErrorAsync("Load Error", ex.Message);
         }
+        finally
+        {
+            _isLoading = false;
+        }
     }
 
     private void LoadSaveFile(SaveFile sav, string path)
@@ -937,7 +949,7 @@ private async Task OpenQRDialogAsync()
 
     public void HandleFileDrop(string[] files)
     {
-        if (files.Length == 0)
+        if (files.Length == 0 || _isLoading)
             return;
 
         _ = LoadFileAsync(files[0]);

PKHeX.Avalonia/ViewModels/PKMEditorViewModel.cs

@@ -994,11 +994,15 @@ private void UpdateBallSprite()
         try
         {
             var skBitmap = SpriteUtil.GetBallSprite(Ball);
-            BallSprite = SKBitmapToAvaloniaBitmapConverter.ToAvaloniaBitmap(skBitmap);
+            var old = BallSprite;
+            BallSprite = SKBitmapToAvaloniaBitmapConverter.ToAvaloniaBitmapAndDispose(skBitmap);
+            old?.Dispose();
         }
         catch
         {
+            var old = BallSprite;
             BallSprite = null;
+            old?.Dispose();
         }
     }
 
@@ -2855,7 +2859,9 @@ private void UpdateLegality()
     {
         if (Entity is null)
         {
+            var old = LegalityImage;
             LegalityImage = null;
+            old?.Dispose();
             Move1Legal = Move2Legal = Move3Legal = Move4Legal = true;
             Relearn1Legal = Relearn2Legal = Relearn3Legal = Relearn4Legal = true;
             return;
@@ -2868,7 +2874,13 @@ private void UpdateLegality()
             var color = valid ? SKColors.Green : SKColors.Red;
 
             using var surface = SKSurface.Create(new SKImageInfo(24, 24));
-            if (surface is null) { LegalityImage = null; return; }
+            if (surface is null)
+            {
+                var old2 = LegalityImage;
+                LegalityImage = null;
+                old2?.Dispose();
+                return;
+            }
             var canvas = surface.Canvas;
             canvas.Clear(SKColors.Transparent);
             using var paint = new SKPaint { Color = color, IsAntialias = true };
@@ -2877,7 +2889,9 @@ private void UpdateLegality()
             using var image = surface.Snapshot();
             using var data = image.Encode(SKEncodedImageFormat.Png, 100);
             using var ms = new MemoryStream(data.ToArray());
+            var oldLegality = LegalityImage;
             LegalityImage = new Bitmap(ms);
+            oldLegality?.Dispose();
 
             // Move legality
             var moves = la.Info.Moves;
@@ -2909,7 +2923,9 @@ private void UpdateLegality()
         }
         catch
         {
+            var old = LegalityImage;
             LegalityImage = null;
+            old?.Dispose();
             Move1Legal = Move2Legal = Move3Legal = Move4Legal = true;
             Relearn1Legal = Relearn2Legal = Relearn3Legal = Relearn4Legal = true;
         }
@@ -2921,6 +2937,9 @@ private void UpdateSprite()
             return;
 
         var sprite = Entity.Sprite();
+        var old = SpriteImage;
         SpriteImage = SKBitmapToAvaloniaBitmapConverter.ToAvaloniaBitmap(sprite);
+        old?.Dispose();
+        sprite.Dispose();
     }
 }

PKHeX.Avalonia/ViewModels/SAVEditorViewModel.cs

@@ -303,11 +303,15 @@ private void RefreshBox()
         try
         {
             var wpBitmap = _sav.WallpaperImage(CurrentBox);
-            BoxWallpaper = SKBitmapToAvaloniaBitmapConverter.ToAvaloniaBitmap(wpBitmap);
+            var oldWp = BoxWallpaper;
+            BoxWallpaper = SKBitmapToAvaloniaBitmapConverter.ToAvaloniaBitmapAndDispose(wpBitmap);
+            oldWp?.Dispose();
         }
         catch
         {
+            var oldWp = BoxWallpaper;
             BoxWallpaper = null;
+            oldWp?.Dispose();
         }
 
         int slotCount = Math.Min(30, _sav.BoxSlotCount);

PKHeX.Avalonia/ViewModels/Subforms/QRDialogViewModel.cs

@@ -34,9 +34,14 @@ private void GenerateQR(PKM pk)
         var qr = QREncode.GenerateQRCode(pk);
         var sprite = pk.Sprite();
         var composed = QRImageUtil.GetQRImage(qr, sprite);
+        qr.Dispose();
+        sprite.Dispose();
 
+        _qrBitmap?.Dispose();
         _qrBitmap = composed;
+        var old = QrImage;
         QrImage = SKBitmapToAvaloniaBitmapConverter.ToAvaloniaBitmap(composed);
+        old?.Dispose();
 
         var lines = pk.GetQRLines();
         SummaryText = string.Join("\n", lines);

PKHeX.Avalonia/ViewModels/Subforms/Trainer8ViewModel.cs

@@ -119,7 +119,7 @@ private void Save()
         _sav.Blocks.TrainerCard.TrainerID = int.TryParse(TrainerCardId, out var tcid) ? tcid : 0;
         _sav.Blocks.TrainerCard.RotoRallyScore = int.TryParse(RotoRallyScore, out var rr) ? rr : 0;
 
-        _sav.Money = uint.TryParse(Money, out var money) ? money : 0u;
+        _sav.Money = uint.TryParse(Money, out var money) ? (uint)Math.Min(money, (uint)_sav.MaxMoney) : 0u;
 
         var watt = uint.TryParse(Watt, out var w) ? w : 0u;
         _sav.MyStatus.Watt = watt;

PKHeX.Avalonia/ViewModels/Subforms/Trainer8aViewModel.cs

@@ -65,7 +65,7 @@ private void Save()
     {
         _sav.Gender = (byte)Gender;
         _sav.OT = OtName;
-        _sav.Money = uint.TryParse(Money, out var money) ? money : 0u;
+        _sav.Money = uint.TryParse(Money, out var money) ? (uint)Math.Min(money, (uint)_sav.MaxMoney) : 0u;
 
         _sav.PlayedHours = (ushort)Math.Clamp(PlayedHours, 0, ushort.MaxValue);
         _sav.PlayedMinutes = (ushort)Math.Clamp(PlayedMinutes, 0, 59);

PKHeX.Avalonia/ViewModels/Subforms/Trainer8bViewModel.cs

@@ -76,7 +76,7 @@ private void Save()
         _sav.Gender = (byte)Gender;
         _sav.OT = OtName;
         _sav.Rival = Rival;
-        _sav.Money = uint.TryParse(Money, out var money) ? money : 0u;
+        _sav.Money = uint.TryParse(Money, out var money) ? (uint)Math.Min(money, (uint)_sav.MaxMoney) : 0u;
         _sav.BattleTower.BP = (uint)Math.Max(0, Bp);
 
         _sav.PlayedHours = (ushort)Math.Clamp(PlayedHours, 0, ushort.MaxValue);

PKHeX.Avalonia/ViewModels/Subforms/Trainer9ViewModel.cs

@@ -182,7 +182,7 @@ private void Save()
         _sav.Version = (GameVersion)(GameIndex + (byte)GameVersion.SL);
         _sav.Gender = (byte)Gender;
         _sav.OT = OtName;
-        _sav.Money = uint.TryParse(Money, out var m) ? m : 0u;
+        _sav.Money = uint.TryParse(Money, out var m) ? (uint)Math.Min(m, (uint)_sav.MaxMoney) : 0u;
         _sav.LeaguePoints = uint.TryParse(LeaguePoints, out var lp) ? lp : 0u;
 
         _sav.PlayedHours = (ushort)Math.Clamp(PlayedHours, 0, ushort.MaxValue);

PKHeX.Avalonia/ViewModels/Subforms/Trainer9aViewModel.cs

@@ -113,7 +113,7 @@ private void Save()
         }
 
         _sav.OT = OtName;
-        _sav.Money = uint.TryParse(Money, out var m) ? m : 0u;
+        _sav.Money = uint.TryParse(Money, out var m) ? (uint)Math.Min(m, (uint)_sav.MaxMoney) : 0u;
 
         _sav.PlayedHours = (ushort)Math.Clamp(PlayedHours, 0, ushort.MaxValue);
         _sav.PlayedMinutes = (ushort)Math.Clamp(PlayedMinutes, 0, 59);

PKHeX.Avalonia/ViewModels/Subforms/WondercardViewModel.cs

@@ -37,7 +37,9 @@ public void Refresh()
         IsEmpty = Gift.IsEmpty;
         Description = IsEmpty ? $"Slot {Index + 1}: (empty)" : $"Slot {Index + 1}: {Gift.CardHeader}";
         var skBitmap = Gift.Sprite();
-        Sprite = SKBitmapToAvaloniaBitmapConverter.ToAvaloniaBitmap(skBitmap);
+        var old = Sprite;
+        Sprite = SKBitmapToAvaloniaBitmapConverter.ToAvaloniaBitmapAndDispose(skBitmap);
+        old?.Dispose();
     }
 
     public void SetGift(DataMysteryGift gift)