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/Tools/IAgentTool.cs

@@ -0,0 +1,15 @@
+using System.Text.Json;
+
+namespace ClawdDotNet.Core.Tools;
+
+public interface IAgentTool
+{
+    string Name { get; }
+    string Description { get; }
+    JsonElement InputSchema { get; }
+
+    Task<ToolResult> ExecuteAsync(
+        JsonElement input,
+        AgentToolContext context,
+        CancellationToken ct);
+}