Initial commit: ClawdDotNet

Import des bestehenden Projektstands in Git.
- .NET 10 WinForms Anwendung (Multi-Agent / Tool-System)
- .gitignore fuer Build-Artefakte, Secrets und Runtime-Daten ergaenzt

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

src/ClawdDotNet.Core/Logging/LogEntry.cs

@@ -0,0 +1,29 @@
+namespace ClawdDotNet.Core.Logging;
+
+public sealed record LogEntry(
+    DateTime Timestamp,
+    LogLevel Level,
+    string Module,
+    string Message,
+    Exception? Exception = null
+)
+{
+    public string Format(string timestampFormat)
+    {
+        var levelTag = Level switch
+        {
+            LogLevel.Debug => "DBG",
+            LogLevel.Info => "INF",
+            LogLevel.Warn => "WRN",
+            LogLevel.Error => "ERR",
+            _ => "???"
+        };
+
+        var line = $"[{Timestamp.ToString(timestampFormat)}] [{levelTag}] {Message}";
+
+        if (Exception is not null)
+            line += Environment.NewLine + Exception.ToString();
+
+        return line;
+    }
+}