第 0 阶段：教材项目 2 任务 1 在网页中原样运行

- runtime：仿真 WinForms 子集（Form、Button、Label、TextBox、ComboBox、
  GroupBox、Timer、MessageBox、界面线程消息循环、跨线程检查）、
  教材设备类库（DeviceCtrlHelper、LED 控件）、运行器（常驻编译服务 + 运行模式）
- server：Bun + Hono，WebSocket 会话，每次运行一个进程，消息转发
- web：Vue + Naive UI，WinForms 风格窗体渲染、MessageBox、实训台 LED 屏
- 端到端测试与 100 个程序并发的压力测试
- 教材逐任务摘要（docs/教材摘要）

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

runtime/Sim.WinForms/Host/PropValue.cs

@@ -0,0 +1,57 @@
+using System;
+using System.Collections;
+using System.Drawing;
+using System.Globalization;
+using System.Text.Json.Nodes;
+using System.Windows.Forms;
+
+namespace Sim.Host;
+
+/// <summary>把控件属性值转换成发给浏览器的 JSON（格式见 web/src/winforms/format.ts）</summary>
+public static class PropValue
+{
+    public static JsonNode? From(object? value) => value switch
+    {
+        null => null,
+        string s => JsonValueOf(s),
+        bool b => JsonValueOf(b),
+        char c => JsonValueOf(c == '\0' ? "" : c.ToString()),
+        int or long or short or byte => JsonValueOf(Convert.ToInt64(value, CultureInfo.InvariantCulture)),
+        float or double or decimal => JsonValueOf(Convert.ToDouble(value, CultureInfo.InvariantCulture)),
+        Enum e => JsonValueOf(e.ToString()),
+        Point p => new JsonObject { ["x"] = p.X, ["y"] = p.Y },
+        Size s => new JsonObject { ["width"] = s.Width, ["height"] = s.Height },
+        Color c => ColorCss(c),
+        Font f => new JsonObject
+        {
+            ["family"] = f.Name,
+            ["size"] = f.SizeInPoints,
+            ["bold"] = f.Bold,
+            ["italic"] = f.Italic,
+            ["underline"] = f.Underline,
+            ["strikeout"] = f.Strikeout,
+        },
+        Padding p => new JsonObject { ["left"] = p.Left, ["top"] = p.Top, ["right"] = p.Right, ["bottom"] = p.Bottom },
+        IEnumerable list => ListOf(list),
+        _ => JsonValueOf(value.ToString() ?? ""),
+    };
+
+    /// <summary>未设置的颜色（Color.Empty）返回 null，表示沿用父控件的颜色</summary>
+    public static JsonNode? ColorCss(Color color)
+    {
+        if (color.IsEmpty) return null;
+        if (color.A == 0) return "transparent";
+        if (color.A < 255)
+            return $"rgba({color.R},{color.G},{color.B},{(color.A / 255.0).ToString("0.###", CultureInfo.InvariantCulture)})";
+        return $"#{color.R:x2}{color.G:x2}{color.B:x2}";
+    }
+
+    private static JsonArray ListOf(IEnumerable items)
+    {
+        var array = new JsonArray();
+        foreach (var item in items) array.Add(From(item is string or null ? item : item.ToString()));
+        return array;
+    }
+
+    private static JsonNode JsonValueOf<T>(T value) => JsonValue.Create(value)!;
+}