Add project restore files and NuGet cache for GsaViewer

- Created project.nuget.cache to store NuGet package cache information.
- Added project.packagespec.json to define project restore settings and dependencies.
- Included rider.project.restore.info for Rider IDE integration.

GsaEditor/Helpers/Dialogs.cs

@@ -0,0 +1,204 @@
+using Avalonia;
+using Avalonia.Controls;
+using Avalonia.Layout;
+
+namespace GsaEditor.Helpers;
+
+/// <summary>
+/// Provides simple dialog utilities (confirm, message, input) using programmatically-created Avalonia windows.
+/// No third-party controls or custom themes are used.
+/// </summary>
+public static class Dialogs
+{
+    /// <summary>
+    /// Shows a confirmation dialog with Yes/No buttons.
+    /// </summary>
+    /// <param name="parent">The parent window.</param>
+    /// <param name="title">Dialog title.</param>
+    /// <param name="message">Message to display.</param>
+    /// <returns>True if the user clicked Yes, false otherwise.</returns>
+    public static async Task<bool> ConfirmAsync(Window parent, string title, string message)
+    {
+        var result = false;
+
+        var dialog = new Window
+        {
+            Title = title,
+            Width = 420,
+            Height = 170,
+            WindowStartupLocation = WindowStartupLocation.CenterOwner,
+            CanResize = false,
+            ShowInTaskbar = false
+        };
+
+        var messageBlock = new TextBlock
+        {
+            Text = message,
+            TextWrapping = Avalonia.Media.TextWrapping.Wrap,
+            Margin = new Thickness(0, 0, 0, 15)
+        };
+
+        var yesButton = new Button
+        {
+            Content = "Yes",
+            Width = 80,
+            HorizontalContentAlignment = HorizontalAlignment.Center
+        };
+        yesButton.Click += (_, _) =>
+        {
+            result = true;
+            dialog.Close();
+        };
+
+        var noButton = new Button
+        {
+            Content = "No",
+            Width = 80,
+            HorizontalContentAlignment = HorizontalAlignment.Center
+        };
+        noButton.Click += (_, _) =>
+        {
+            result = false;
+            dialog.Close();
+        };
+
+        var buttonPanel = new StackPanel
+        {
+            Orientation = Orientation.Horizontal,
+            HorizontalAlignment = HorizontalAlignment.Right,
+            Spacing = 10,
+            Children = { yesButton, noButton }
+        };
+
+        dialog.Content = new StackPanel
+        {
+            Margin = new Thickness(20),
+            Spacing = 5,
+            Children = { messageBlock, buttonPanel }
+        };
+
+        await dialog.ShowDialog(parent);
+        return result;
+    }
+
+    /// <summary>
+    /// Shows a simple message dialog with an OK button.
+    /// </summary>
+    /// <param name="parent">The parent window.</param>
+    /// <param name="title">Dialog title.</param>
+    /// <param name="message">Message to display.</param>
+    public static async Task ShowMessageAsync(Window parent, string title, string message)
+    {
+        var dialog = new Window
+        {
+            Title = title,
+            Width = 420,
+            Height = 180,
+            WindowStartupLocation = WindowStartupLocation.CenterOwner,
+            CanResize = false,
+            ShowInTaskbar = false
+        };
+
+        var messageBlock = new TextBlock
+        {
+            Text = message,
+            TextWrapping = Avalonia.Media.TextWrapping.Wrap,
+            Margin = new Thickness(0, 0, 0, 15)
+        };
+
+        var okButton = new Button
+        {
+            Content = "OK",
+            Width = 80,
+            HorizontalAlignment = HorizontalAlignment.Right,
+            HorizontalContentAlignment = HorizontalAlignment.Center
+        };
+        okButton.Click += (_, _) => dialog.Close();
+
+        dialog.Content = new StackPanel
+        {
+            Margin = new Thickness(20),
+            Spacing = 5,
+            Children = { messageBlock, okButton }
+        };
+
+        await dialog.ShowDialog(parent);
+    }
+
+    /// <summary>
+    /// Shows an input dialog with a text box, OK and Cancel buttons.
+    /// </summary>
+    /// <param name="parent">The parent window.</param>
+    /// <param name="title">Dialog title.</param>
+    /// <param name="prompt">Prompt text shown above the input.</param>
+    /// <param name="defaultValue">Default value in the text box.</param>
+    /// <returns>The entered string, or null if cancelled.</returns>
+    public static async Task<string?> InputAsync(Window parent, string title, string prompt, string defaultValue = "")
+    {
+        string? result = null;
+
+        var dialog = new Window
+        {
+            Title = title,
+            Width = 450,
+            Height = 180,
+            WindowStartupLocation = WindowStartupLocation.CenterOwner,
+            CanResize = false,
+            ShowInTaskbar = false
+        };
+
+        var promptBlock = new TextBlock
+        {
+            Text = prompt,
+            Margin = new Thickness(0, 0, 0, 5)
+        };
+
+        var textBox = new TextBox
+        {
+            Text = defaultValue,
+            Margin = new Thickness(0, 0, 0, 10)
+        };
+
+        var okButton = new Button
+        {
+            Content = "OK",
+            Width = 80,
+            HorizontalContentAlignment = HorizontalAlignment.Center
+        };
+        okButton.Click += (_, _) =>
+        {
+            result = textBox.Text;
+            dialog.Close();
+        };
+
+        var cancelButton = new Button
+        {
+            Content = "Cancel",
+            Width = 80,
+            HorizontalContentAlignment = HorizontalAlignment.Center
+        };
+        cancelButton.Click += (_, _) =>
+        {
+            result = null;
+            dialog.Close();
+        };
+
+        var buttonPanel = new StackPanel
+        {
+            Orientation = Orientation.Horizontal,
+            HorizontalAlignment = HorizontalAlignment.Right,
+            Spacing = 10,
+            Children = { okButton, cancelButton }
+        };
+
+        dialog.Content = new StackPanel
+        {
+            Margin = new Thickness(20),
+            Spacing = 5,
+            Children = { promptBlock, textBox, buttonPanel }
+        };
+
+        await dialog.ShowDialog(parent);
+        return result;
+    }
+}

GsaEditor/Helpers/HexDumper.cs

@@ -0,0 +1,59 @@
+using System.Text;
+
+namespace GsaEditor.Helpers;
+
+/// <summary>
+/// Produces a classic hex + ASCII dump string from a byte array.
+/// </summary>
+public static class HexDumper
+{
+    /// <summary>
+    /// Formats a byte array as a hex dump with offset, hex values, and printable ASCII characters.
+    /// </summary>
+    /// <param name="data">The data to dump.</param>
+    /// <param name="maxBytes">Maximum number of bytes to include in the dump.</param>
+    /// <returns>A formatted hex dump string.</returns>
+    public static string Dump(byte[] data, int maxBytes = 512)
+    {
+        var sb = new StringBuilder();
+        int length = Math.Min(data.Length, maxBytes);
+        const int bytesPerLine = 16;
+
+        for (int offset = 0; offset < length; offset += bytesPerLine)
+        {
+            // Offset column
+            sb.Append($"{offset:X8}  ");
+
+            int lineLen = Math.Min(bytesPerLine, length - offset);
+
+            // Hex columns
+            for (int i = 0; i < bytesPerLine; i++)
+            {
+                if (i < lineLen)
+                    sb.Append($"{data[offset + i]:X2} ");
+                else
+                    sb.Append("   ");
+
+                if (i == 7) sb.Append(' ');
+            }
+
+            sb.Append(' ');
+
+            // ASCII column
+            for (int i = 0; i < lineLen; i++)
+            {
+                byte b = data[offset + i];
+                sb.Append(b >= 0x20 && b < 0x7F ? (char)b : '.');
+            }
+
+            sb.AppendLine();
+        }
+
+        if (data.Length > maxBytes)
+        {
+            sb.AppendLine($"... ({data.Length - maxBytes} more bytes)");
+        }
+
+        return sb.ToString();
+    }
+}