feat: send_to_session tool – agent-to-agent messaging

- Neues Tool send_to_session: Agent kann Nachrichten in andere Sessions schicken
- Ziel-Session per ID oder Name (case-insensitive) auffindbar
- User-Message wird nicht in DB gespeichert (wie Cronjob) – keine Bubble im Frontend
- Nachricht wird als '[Nachricht von Agent "X"]' kontextualisiert injiziert
- Sicherheitscheck: Ziel-Session muss demselben User gehören, keine eigene Session
- Zirkuläre Abhängigkeit ChatService ↔ AnthropicService via SetChatService() gelöst
- tool-ui.js: Display-Name für send_to_session

Services/AnthropicService.cs

@@ -24,6 +24,7 @@ public class AnthropicService
     private readonly bool _payloadLoggingGzip;
     private readonly VectorSearchService _vectorSearch;
     private readonly EmbeddingBackgroundService _embeddingBg;
+    private ChatService _chatService;
 
     public AnthropicService(IHttpClientFactory httpFactory, string token, ToolService toolService, DatabaseService db, MemoryService memoryService = null, bool payloadLogging = false, bool payloadLoggingGzip = false, VectorSearchService vectorSearch = null, EmbeddingBackgroundService embeddingBg = null)
     {
@@ -38,6 +39,15 @@ public class AnthropicService
         _embeddingBg = embeddingBg;
     }
 
+    /// <summary>
+    /// Wird nach der Konstruktion gesetzt um zirkuläre Abhängigkeit zu vermeiden
+    /// (ChatService → AnthropicService → ChatService).
+    /// </summary>
+    public void SetChatService(ChatService chatService)
+    {
+        _chatService = chatService;
+    }
+
     public async Task StreamChat(
         HttpResponse response,
         string modelId,
@@ -47,6 +57,7 @@ public class AnthropicService
         string workspace,
         string sessionId = null,
         string agentId = null,
+        string userId = null,
         bool useMemory = true,
         string webSearchVersion = null,
         int maxIterations = 100,
@@ -183,7 +194,7 @@ public class AnthropicService
                     return;
                 }
 
-                var (stopReason, assistantContent, executedTools, streamErrorInfo) = await ProcessStream(response, httpResp, usage, workspace, agentId, workCt, sseCt, remoteMgr, sessionId);
+                var (stopReason, assistantContent, executedTools, streamErrorInfo) = await ProcessStream(response, httpResp, usage, workspace, agentId, workCt, sseCt, remoteMgr, sessionId, userId);
                 lastStopReason = stopReason;
                 promptTrimRetries = 0; // Erfolgreicher API-Call → Retry-Counter resetten
 
@@ -1204,7 +1215,8 @@ public class AnthropicService
         CancellationToken workCt = default,
         CancellationToken sseCt = default,
         RemoteConnectionManager remoteMgr = null,
-        string sessionId = null)
+        string sessionId = null,
+        string userId = null)
     {
         var stream = await httpResp.Content.ReadAsStreamAsync(workCt);
         // Bei Cancellation den Stream disposen, damit ReadLineAsync sofort abbricht.
@@ -1386,7 +1398,7 @@ public class AnthropicService
 
                             string toolResult;
                             bool isError = false;
-                            try { toolResult = await _toolService.ExecuteTool(currentToolName, inputEl, workspace, _memoryService, agentId, workCt, remoteMgr: remoteMgr, sessionId: sessionId, vectorSearch: _vectorSearch, embeddingBg: _embeddingBg); }
+                            try { toolResult = await _toolService.ExecuteTool(currentToolName, inputEl, workspace, _memoryService, agentId, workCt, remoteMgr: remoteMgr, sessionId: sessionId, vectorSearch: _vectorSearch, embeddingBg: _embeddingBg, db: _db, chatService: _chatService, anthropicService: this, userId: userId); }
                             catch (OperationCanceledException) { throw; }
                             catch (Exception ex) { toolResult = $"Fehler: {ex.Message}"; isError = true; }
 
@@ -1593,7 +1605,8 @@ public class AnthropicService
         var hasWorkspace = !string.IsNullOrEmpty(workspace);
         var includeMemory = useMemory && _memoryService != null && !string.IsNullOrEmpty(agentId);
         var includeMemorySearch = _vectorSearch != null && _vectorSearch.GetEmbeddingCount() > 0;
-        var hasTools = hasWorkspace || includeMemory || includeRemote || includeMemorySearch;
+        var includeSendToSession = _db != null && _chatService != null;
+        var hasTools = hasWorkspace || includeMemory || includeRemote || includeMemorySearch || includeSendToSession;
         var hasWebSearch = !string.IsNullOrEmpty(webSearchVersion);
 
         if (!hasTools && !hasWebSearch) return;
@@ -1601,7 +1614,7 @@ public class AnthropicService
         var tools = new List<object>();
         if (hasTools)
         {
-            var allTools = _toolService.GetToolDefinitions(includeFileTools: hasWorkspace, includeMemory: includeMemory, includeUserChoice: allowUserChoice, includeRemote: includeRemote, includeMemorySearch: includeMemorySearch);
+            var allTools = _toolService.GetToolDefinitions(includeFileTools: hasWorkspace, includeMemory: includeMemory, includeUserChoice: allowUserChoice, includeRemote: includeRemote, includeMemorySearch: includeMemorySearch, includeSendToSession: includeSendToSession);
             if (planMode)
                 allTools = _toolService.FilterReadOnlyTools(allTools);
             tools.AddRange(allTools);