feat: add ClientGeneratorService for single-file client/upgrade code (#34)

- Generates client.cs and upgrade.cs using #r nuget: inline references
- Client uses GeneralUpdate.ClientCore to poll for updates
- Upgrade uses GeneralUpdate.Core to apply patches
- Templates replace placeholders (version, URL, keys, paths)
- Added ServerPort to SimulateConfigModel

Author: JusterZhu

src/Models/SimulateConfigModel.cs

@@ -33,4 +33,7 @@ public partial class SimulateConfigModel : ObservableObject
 
     /// <summary>Directory where client.cs / upgrade.cs and server are generated.</summary>
     [ObservableProperty] private string _outputDirectory = string.Empty;
+
+    /// <summary>Server port assigned at runtime (set by SimulationService).</summary>
+    public int ServerPort { get; set; } = 5000;
 }

src/Services/ClientGeneratorService.cs

@@ -0,0 +1,147 @@
+using System;
+using System.IO;
+using System.Text;
+using System.Threading.Tasks;
+using GeneralUpdate.Tools.Models;
+
+namespace GeneralUpdate.Tools.Services;
+
+/// <summary>
+/// Generates single-file client.cs and upgrade.cs for simulation,
+/// using dotnet-run (#r nuget:...) without project files.
+/// </summary>
+public class ClientGeneratorService
+{
+    private const string ClientTemplate = """
+#r "nuget: GeneralUpdate.ClientCore, 10.*"
+#r "nuget: GeneralUpdate.Core, 10.*"
+
+using GeneralUpdate.ClientCore;
+using GeneralUpdate.Common.Shared.Object;
+using GeneralUpdate.Common.Internal.Event;
+
+var log = (string msg) => Console.WriteLine($"[{DateTime.Now:HH:mm:ss}] {msg}");
+
+try
+{{
+    log("Client started");
+    log("Install path: {0}");
+
+    var config = new Configinfo
+    {{
+        ReportUrl = "{1}/Upgrade/Report",
+        UpdateUrl = "{1}/Upgrade/Verification",
+        AppName = "{2}",
+        MainAppName = "{3}",
+        InstallPath = @"{0}",
+        ClientVersion = "{4}",
+        UpgradeClientVersion = "{5}",
+        ProductId = "{6}",
+        AppSecretKey = "{7}",
+    }};
+
+    await new GeneralClientBootstrap()
+        .SetConfig(config)
+        .AddListenerMultiDownloadStatistics((_, e) =>
+        {{
+            var v = e.Version as VersionInfo;
+            log($"Download: {{v?.Version}} {{e.ProgressPercentage}}% {{e.Speed}}/s");
+        }})
+        .AddListenerMultiAllDownloadCompleted((_, e) =>
+        {{
+            log(e.IsAllDownloadCompleted ? "All downloads completed" : $"Download failed: {{e.FailedVersions.Count}}");
+        }})
+        .AddListenerException((_, e) =>
+        {{
+            log($"ERROR: {{e.Exception}}");
+        }})
+        .AddListenerUpdateInfo((_, e) =>
+        {{
+            log($"Update info: Code={{e.Info.Code}}, Versions={{e.Info.Body?.Count ?? 0}}");
+        }})
+        .LaunchAsync();
+
+    log("Update process completed");
+}}
+catch (Exception ex)
+{{
+    log($"FATAL: {{ex.Message}}");
+    Console.Error.WriteLine(ex);
+    Environment.Exit(1);
+}}
+""";
+
+    private const string UpgradeTemplate = """
+#r "nuget: GeneralUpdate.Core, 10.*"
+#r "nuget: GeneralUpdate.ClientCore, 10.*"
+
+using GeneralUpdate.Core;
+using GeneralUpdate.Common.Shared;
+using GeneralUpdate.Common.Internal.Event;
+
+var log = (string msg) => Console.WriteLine($"[{DateTime.Now:HH:mm:ss}] {msg}");
+
+try
+{{
+    log("Upgrade process started");
+    log("Working directory: " + Environment.CurrentDirectory);
+
+    await new GeneralUpdateBootstrap()
+        .AddListenerMultiDownloadStatistics((_, e) =>
+        {{
+            var v = e.Version as GeneralUpdate.Common.Shared.Object.VersionInfo;
+            log($"Download: {{v?.Version}} {{e.ProgressPercentage}}%");
+        }})
+        .AddListenerMultiAllDownloadCompleted((_, e) =>
+        {{
+            log(e.IsAllDownloadCompleted ? "Downloads done" : "Download failed");
+        }})
+        .AddListenerException((_, e) =>
+        {{
+            log($"ERROR: {{e.Exception}}");
+        }})
+        .LaunchAsync();
+
+    log("Upgrade process finished successfully");
+}}
+catch (Exception ex)
+{{
+    log($"FATAL: {{ex.Message}}");
+    Console.Error.WriteLine(ex);
+    Environment.Exit(1);
+}}
+""";
+
+    public async Task GenerateAsync(SimulateConfigModel config, string outputDir)
+    {
+        var serverUrl = $"http://127.0.0.1:{config.ServerPort}";
+
+        // client.cs
+        var clientCode = string.Format(ClientTemplate,
+            EscapeForCSharp(config.AppDirectory),
+            serverUrl,
+            "upgrade.cs",              // AppName - the upgrade process
+            "client.cs",               // MainAppName
+            config.CurrentVersion,
+            "1.0.0.0",                 // upgrade client version
+            config.ProductId,
+            config.AppSecretKey);
+
+        await File.WriteAllTextAsync(
+            Path.Combine(outputDir, "client.cs"),
+            clientCode,
+            Encoding.UTF8);
+
+        // upgrade.cs
+        var upgradeCode = string.Format(UpgradeTemplate,
+            EscapeForCSharp(config.AppDirectory));
+
+        await File.WriteAllTextAsync(
+            Path.Combine(outputDir, "upgrade.cs"),
+            upgradeCode,
+            Encoding.UTF8);
+    }
+
+    private static string EscapeForCSharp(string s) =>
+        s.Replace(@"\", @"\\").Replace("\"", "\\\"");
+}