feat: 初始功能

Models/AppLogEntry.cs

@@ -0,0 +1,39 @@
+namespace CloudPrint.Client.Models;
+
+public enum AppLogLevel
+{
+    Info,
+    Success,
+    Warning,
+    Error
+}
+
+public sealed class AppLogEntry
+{
+    public DateTime Timestamp { get; init; } = DateTime.Now;
+    public AppLogLevel Level { get; init; } = AppLogLevel.Info;
+    public string Message { get; init; } = string.Empty;
+    public string ExceptionText { get; init; } = string.Empty;
+
+    public string LevelText => Level switch
+    {
+        AppLogLevel.Success => "成功",
+        AppLogLevel.Warning => "警告",
+        AppLogLevel.Error => "错误",
+        _ => "信息"
+    };
+
+    public string DisplayText => string.IsNullOrWhiteSpace(ExceptionText)
+        ? $"[{Timestamp:HH:mm:ss}] [{LevelText}] {Message}"
+        : $"[{Timestamp:HH:mm:ss}] [{LevelText}] {Message}（详见本地日志）";
+
+    public static AppLogEntry FromException(string message, Exception exception)
+    {
+        return new AppLogEntry
+        {
+            Level = AppLogLevel.Error,
+            Message = message,
+            ExceptionText = exception.ToString()
+        };
+    }
+}