feat: add embedded ASP.NET LocalUpdateServer for simulate module (#33)

- Add FrameworkReference Microsoft.AspNetCore.App
- LocalUpdateServer: minimal API with three endpoints
  - GET /Upgrade/Verification - returns version info with local patch URL
  - POST /Upgrade/Report - accepts update status reports
  - GET /patch/{filename} - serves patch .zip files
- Auto-detect bound port, static file lookup for patches

Author: JusterZhu

src/GeneralUpdate.Tools.csproj

@@ -31,4 +31,8 @@
     <PackageReference Include="GeneralUpdate.Core" Version="10.4.6" />
     <PackageReference Include="Newtonsoft.Json" Version="13.0.3" />
   </ItemGroup>
+
+  <ItemGroup>
+    <FrameworkReference Include="Microsoft.AspNetCore.App" />
+  </ItemGroup>
 </Project>

src/Services/LocalUpdateServer.cs

@@ -0,0 +1,104 @@
+using System;
+using System.Collections.Generic;
+using System.IO;
+using System.Linq;
+using System.Threading.Tasks;
+using Microsoft.AspNetCore.Builder;
+using Microsoft.AspNetCore.Hosting;
+using Microsoft.AspNetCore.Http;
+using Microsoft.Extensions.DependencyInjection;
+using Microsoft.Extensions.Hosting;
+
+namespace GeneralUpdate.Tools.Services;
+
+public class LocalUpdateServer : IAsyncDisposable
+{
+    private WebApplication? _app;
+    private int _port;
+    private Task? _runTask;
+
+    public int Port => _port;
+    public string BaseUrl => $"http://127.0.0.1:{_port}";
+
+    public List<(string CurrentVersion, string TargetVersion, string Hash, string ZipPath, int AppType)> Updates { get; } = new();
+
+    public async Task StartAsync(int port = 5000)
+    {
+        var builder = WebApplication.CreateBuilder();
+        builder.WebHost.UseUrls($"http://127.0.0.1:{port}");
+
+        _app = builder.Build();
+
+        // GET /Upgrade/Verification
+        _app.MapGet("/Upgrade/Verification", async (HttpContext context) =>
+        {
+            var q = context.Request.Query;
+            var currentVer = q["currentVersion"].ToString();
+            _ = int.TryParse(q["appType"].ToString(), out var appType);
+
+            var match = Updates.Find(u => u.CurrentVersion == currentVer);
+            if (match == default)
+            {
+                await context.Response.WriteAsJsonAsync(new { code = 204, body = Array.Empty<object>() });
+                return;
+            }
+
+            var body = new[]
+            {
+                new
+                {
+                    name = Path.GetFileName(match.ZipPath),
+                    version = match.TargetVersion,
+                    hash = match.Hash,
+                    url = $"{BaseUrl}/patch/{Uri.EscapeDataString(Path.GetFileName(match.ZipPath))}",
+                    appType = match.AppType,
+                    releaseDate = DateTime.UtcNow.ToString("yyyy-MM-ddTHH:mm:ssZ"),
+                    isForcibly = false
+                }
+            };
+            await context.Response.WriteAsJsonAsync(new { code = 200, body });
+        });
+
+        // POST /Upgrade/Report
+        _app.MapPost("/Upgrade/Report", () => Results.Ok(new { code = 200 }));
+
+        // GET /patch/{filename}
+        _app.MapGet("/patch/{filename}", async (string filename) =>
+        {
+            var filePath = LocalUpdateServerFiles.TryGet(filename);
+            if (filePath == null || !File.Exists(filePath))
+                return Results.NotFound();
+            return Results.File(filePath, "application/zip", filename);
+        });
+
+        _runTask = _app.RunAsync();
+        // Give Kestrel a moment to bind
+        await Task.Delay(500);
+        // Read actual port from addresses
+        var urls = _app.Urls;
+        if (urls.Count > 0)
+        {
+            var uri = new Uri(urls.First());
+            _port = uri.Port;
+        }
+    }
+
+    public async ValueTask DisposeAsync()
+    {
+        if (_app != null)
+        {
+            await _app.StopAsync();
+            await _app.DisposeAsync();
+        }
+        if (_runTask != null)
+            await _runTask;
+    }
+}
+
+internal static class LocalUpdateServerFiles
+{
+    private static readonly Dictionary<string, string> _files = new();
+    public static void Register(string filename, string filePath) => _files[filename] = filePath;
+    public static string? TryGet(string filename) => _files.TryGetValue(filename, out var p) ? p : null;
+    public static void Clear() => _files.Clear();
+}