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/Api/OpenRouterClient.cs

@@ -0,0 +1,120 @@
+using System.Net.Http.Headers;
+using System.Text;
+using System.Text.Json;
+using ClawdDotNet.Core.Api.Models;
+using Microsoft.Extensions.Logging;
+
+namespace ClawdDotNet.Core.Api;
+
+public sealed class OpenRouterClient : IDisposable
+{
+    private const string BaseUrl = "https://openrouter.ai/api/v1/";
+
+    private readonly HttpClient _http;
+    private readonly ILogger _logger;
+
+    private static readonly JsonSerializerOptions JsonOptions = new()
+    {
+        DefaultIgnoreCondition = System.Text.Json.Serialization.JsonIgnoreCondition.WhenWritingNull
+    };
+
+    public OpenRouterClient(string apiKey, ILogger logger, HttpClient? httpClient = null)
+    {
+        _logger = logger;
+        _http = httpClient ?? new HttpClient();
+        _http.BaseAddress = new Uri(BaseUrl);
+        _http.Timeout = TimeSpan.FromMinutes(5); // LLM-Calls können bei großen Prompts lange dauern
+        _http.DefaultRequestHeaders.Authorization = new AuthenticationHeaderValue("Bearer", apiKey);
+        _http.DefaultRequestHeaders.Add("HTTP-Referer", "ClawdDotNet");
+        _http.DefaultRequestHeaders.Add("X-Title", "ClawdDotNet");
+    }
+
+    public async Task<ChatResponse> CompleteAsync(ChatRequest request, CancellationToken ct)
+    {
+        request.Stream = false;
+
+        var json = JsonSerializer.Serialize(request, JsonOptions);
+        using var content = new StringContent(json, Encoding.UTF8, "application/json");
+
+        _logger.LogDebug("Sending request to OpenRouter: model={Model}, messages={Count}",
+            request.Model, request.Messages.Count);
+
+        using var response = await _http.PostAsync("chat/completions", content, ct);
+        var responseBody = await response.Content.ReadAsStringAsync(ct);
+
+        if (!response.IsSuccessStatusCode)
+        {
+            _logger.LogError("OpenRouter API error {StatusCode}: {Body}",
+                (int)response.StatusCode, responseBody);
+            throw new OpenRouterException(
+                $"API request failed with status {(int)response.StatusCode}",
+                (int)response.StatusCode,
+                responseBody);
+        }
+
+        var result = JsonSerializer.Deserialize<ChatResponse>(responseBody, JsonOptions)
+            ?? throw new OpenRouterException("Empty response from OpenRouter", 0, responseBody);
+
+        if (result.Error is not null)
+        {
+            _logger.LogError("OpenRouter returned error: {Error}", result.Error.Message);
+            throw new OpenRouterException(result.Error.Message, result.Error.Code ?? 0, responseBody);
+        }
+
+        _logger.LogDebug("OpenRouter response received: tokens={Tokens}",
+            result.Usage?.TotalTokens ?? 0);
+
+        return result;
+    }
+
+    /// <summary>
+    /// Ruft die verfügbaren Modelle von OpenRouter ab (/models Endpoint).
+    /// Gibt eine Liste von Modell-IDs zurück, sortiert nach Name.
+    /// </summary>
+    public async Task<List<ModelInfo>> GetAvailableModelsAsync(CancellationToken ct = default)
+    {
+        _logger.LogDebug("Fetching available models from OpenRouter...");
+
+        using var response = await _http.GetAsync("models", ct);
+        var body = await response.Content.ReadAsStringAsync(ct);
+
+        if (!response.IsSuccessStatusCode)
+        {
+            _logger.LogError("Failed to fetch models: {StatusCode} {Body}",
+                (int)response.StatusCode, body);
+            return [];
+        }
+
+        var doc = JsonDocument.Parse(body);
+
+        if (!doc.RootElement.TryGetProperty("data", out var dataArray))
+            return [];
+
+        var models = new List<ModelInfo>();
+
+        foreach (var item in dataArray.EnumerateArray())
+        {
+            var id = item.GetProperty("id").GetString() ?? "";
+            var name = item.TryGetProperty("name", out var nameProp) ? nameProp.GetString() ?? id : id;
+
+            models.Add(new ModelInfo { Id = id, Name = name });
+        }
+
+        models.Sort((a, b) => string.Compare(a.Id, b.Id, StringComparison.OrdinalIgnoreCase));
+
+        _logger.LogDebug("Fetched {Count} models from OpenRouter", models.Count);
+        return models;
+    }
+
+    public void Dispose()
+    {
+        _http.Dispose();
+    }
+}
+
+public sealed class OpenRouterException(string message, int statusCode, string responseBody)
+    : Exception(message)
+{
+    public int StatusCode { get; } = statusCode;
+    public string ResponseBody { get; } = responseBody;
+}