Nachfassen (#646): TaskFollowUp ueber BuildTaskboard an den Host reichen

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

src/ClawdDotNet.App/AppHost.cs

@@ -666,7 +666,7 @@ public sealed class AppHost : IAsyncDisposable
 
         engine.LoadPersistedChats();
 
-        var (scanner, staging, board) = BuildTaskboard(
+        var (scanner, staging, board, followUp) = BuildTaskboard(
             instance, taskRepository, engine, tools, stateStore, audit,
             stagingRepository, dauerfreigaben, stagingGate, cases, storage, loggerFactory, logger);
 
@@ -737,6 +737,7 @@ public sealed class AppHost : IAsyncDisposable
             loggerFactory.CreateLogger("ClawdDotNet.Core.Audit"));
         auditArchive.Start();
         host.AuditArchive = auditArchive;
+        host.FollowUp = followUp;
         host._shutdown.Add(auditArchive.DisposeAsync);
 
         // #698: what holds in a unit, set by its lead.
@@ -877,7 +878,7 @@ public sealed class AppHost : IAsyncDisposable
         }
     }
 
-    private static (TaskScanner?, StagingService?, TaskboardService?) BuildTaskboard(
+    private static (TaskScanner?, StagingService?, TaskboardService?, Core.Tasks.TaskFollowUp?) BuildTaskboard(
         InstanceConfig instance,
         SqliteTaskRepository taskRepository,
         AgentEngine engine,
@@ -897,7 +898,7 @@ public sealed class AppHost : IAsyncDisposable
             .FirstOrDefault(p => !string.IsNullOrWhiteSpace(p));
 
         if (string.IsNullOrWhiteSpace(sharedWorkspace))
-            return (null, null, null);
+            return (null, null, null, null);
 
         var board = new TaskboardService(taskRepository, Path.Combine(sharedWorkspace, "tasks"));
 
@@ -943,7 +944,6 @@ public sealed class AppHost : IAsyncDisposable
         // #646: the board follows up on stalled, unblocked and waiting work.
         var followUp = new Core.Tasks.TaskFollowUp(board, taskRepository, audit, storage, () => instance.FollowUp,
             () => engine.OrganisationProvider?.Invoke(), loggerFactory.CreateLogger("ClawdDotNet.Core.Tasks.FollowUp"));
-        host.FollowUp = followUp;
 
         var scanner = new TaskScanner(taskRepository, dispatcher, loggerFactory,
             maxParallelRuns: instance.MaxParallelTaskRuns,
@@ -1023,7 +1023,7 @@ public sealed class AppHost : IAsyncDisposable
             }
         });
 
-        return (scanner, staging, board);
+        return (scanner, staging, board, followUp);
     }
 
     private async Task ConnectTelegramAsync(Callbacks callbacks, ILogger logger)