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/Config/ConfigLoader.cs

@@ -0,0 +1,42 @@
+using System.Text.Json;
+
+namespace ClawdDotNet.Core.Config;
+
+public static class ConfigLoader
+{
+    private static readonly JsonSerializerOptions JsonOptions = new()
+    {
+        ReadCommentHandling = JsonCommentHandling.Skip,
+        AllowTrailingCommas = true,
+        PropertyNameCaseInsensitive = true
+    };
+
+    public static async Task<InstanceConfig> LoadAsync(string filePath, CancellationToken ct = default)
+    {
+        if (!File.Exists(filePath))
+            throw new FileNotFoundException($"Config file not found: {filePath}");
+
+        await using var stream = File.OpenRead(filePath);
+        var config = await JsonSerializer.DeserializeAsync<InstanceConfig>(stream, JsonOptions, ct)
+            ?? throw new InvalidOperationException($"Config file is empty or invalid: {filePath}");
+
+        Validate(config, filePath);
+        return config;
+    }
+
+    private static void Validate(InstanceConfig config, string filePath)
+    {
+        if (string.IsNullOrWhiteSpace(config.OpenRouterApiKey))
+            throw new InvalidOperationException($"'openRouterApiKey' is required in {filePath}");
+
+        var agentIds = new HashSet<string>();
+        foreach (var agent in config.Agents)
+        {
+            if (string.IsNullOrWhiteSpace(agent.AgentId))
+                throw new InvalidOperationException($"Every agent must have an 'agentId' in {filePath}");
+
+            if (!agentIds.Add(agent.AgentId))
+                throw new InvalidOperationException($"Duplicate agentId '{agent.AgentId}' in {filePath}");
+        }
+    }
+}