Initial commit: WpywMail 自建邮件系统：.NET 8 原生 SMTP/IMAP 服务端（DKIM 签名、SPF/DKIM/DMARC 入站校验、SQLite 存储、完整账号体系）、Node 服务端、WinUI 3 客户端与 Web 前端

server-native-v2/AppLog.cs

@@ -0,0 +1,54 @@
+using System.Text;
+
+namespace WpywMail.Native;
+
+/// <summary>极简日志：控制台 + 文件（超过阈值自动滚动一次）。</summary>
+public static class AppLog
+{
+    private const long MaxBytes = 20 * 1024 * 1024;
+    private static readonly object Gate = new();
+    private static string path = "";
+    private static bool consoleEnabled = true;
+
+    public static void Configure(AppConfig config, bool enableConsole = true)
+    {
+        Directory.CreateDirectory(config.DataDirectory);
+        path = Path.Combine(config.DataDirectory, "service.log");
+        consoleEnabled = enableConsole;
+        Roll();
+        Info($"日志系统已启动（版本 {BuildInfo.Version}）。");
+    }
+
+    public static void Info(string message) => Write("信息", message);
+    public static void Warn(string message) => Write("警告", message);
+    public static void Error(string message) => Write("错误", message);
+
+    private static void Write(string level, string message)
+    {
+        var line = $"{DateTimeOffset.Now:yyyy-MM-dd HH:mm:ss zzz} [{level}] {message}";
+        if (consoleEnabled)
+        {
+            try { Console.WriteLine(line); } catch { }
+        }
+        if (string.IsNullOrWhiteSpace(path)) return;
+        try
+        {
+            lock (Gate) File.AppendAllText(path, line + Environment.NewLine, new UTF8Encoding(false));
+        }
+        catch { }
+    }
+
+    private static void Roll()
+    {
+        try
+        {
+            if (!File.Exists(path)) return;
+            var info = new FileInfo(path);
+            if (info.Length < MaxBytes) return;
+            var backup = path + ".1";
+            if (File.Exists(backup)) File.Delete(backup);
+            File.Move(path, backup);
+        }
+        catch { }
+    }
+}