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/Security/PermissionGate.cs

@@ -0,0 +1,18 @@
+using ClawdDotNet.Core.Config;
+
+namespace ClawdDotNet.Core.Security;
+
+public sealed class PermissionGate
+{
+    public bool IsAllowed(string agentId, string toolName, AgentConfig agentConfig)
+        => agentConfig.Tools.ContainsKey(toolName);
+
+    public void Enforce(string agentId, string toolName, AgentConfig agentConfig)
+    {
+        if (!IsAllowed(agentId, toolName, agentConfig))
+            throw new ToolAccessDeniedException(agentId, toolName);
+    }
+}
+
+public sealed class ToolAccessDeniedException(string agentId, string toolName)
+    : Exception($"Agent '{agentId}' has no access to tool '{toolName}'.");