feat: complete task board workflow gates

backend/Services/TaskService.cs

@@ -9,12 +9,10 @@ public sealed class TaskService(
     ITaskRepository taskRepo,
     IActivityRepository activityRepo,
     INotificationService notificationService,
+    IAgentService agentService,
     IHttpContextAccessor httpContextAccessor,
     ILiveUpdateService liveUpdateService) : ITaskService
 {
-    private static readonly HashSet<string> ValidAssignees =
-        ["bao", "iris", "programmer", "reviewer", "architekt", "researcher", "executor"];
-
     public async Task<IReadOnlyList<WorkTask>> GetAllAsync(CancellationToken ct = default)
         => await taskRepo.GetAllAsync(ct);
 
@@ -90,12 +88,7 @@ public sealed class TaskService(
         if (!TaskStateHelper.CanChangeState(caller, task))
             return new TaskOperationResult(TaskOperationOutcome.InvalidState);
 
-        task.State = canonical;
-        await taskRepo.UpdateAsync(task, ct);
-        await activityRepo.AddAsync(new ActivityEvent { Type = "task", Message = $"Task {task.Title} moved to {task.State}", TaskId = task.Id }, ct);
-        await CreateStatusChangeNotificationsAsync(task, canonical, ct);
-        await PublishBoardSnapshotAsync(ct);
-        return new TaskOperationResult(TaskOperationOutcome.Success, task);
+        return await UpdateTaskStatusInternalAsync(task, canonical, caller, "task", $"Task {task.Title} moved to {canonical}", ct);
     }
 
     public async Task<TaskOperationResult> UpdateAsync(Guid id, UpdateTaskRequest request, CancellationToken ct = default)
@@ -204,7 +197,7 @@ public sealed class TaskService(
         }
 
         var normalizedSource = string.IsNullOrWhiteSpace(source) ? "bao" : source.Trim().ToLowerInvariant();
-        var normalizedAssignee = ValidateAssignedTo(assignedTo);
+        var normalizedAssignee = await NormalizeActorAsync(assignedTo, ct);
         var isVisibleDelegation = parentTaskId.HasValue;
 
         var task = new WorkTask
@@ -250,14 +243,14 @@ public sealed class TaskService(
 
     public async Task<WorkTask> CreateAgentTaskAsync(
         string title, string? detail, string? source, string? priority,
-        string? assignedTo, string? expectedFrom, Guid? parentTaskId = null, CancellationToken ct = default)
+        string? assignedTo, string? expectedFrom, Guid? parentTaskId = null, bool startsInProgress = true, string? initialState = null, CancellationToken ct = default)
     {
-        var normalizedExpectedFrom = string.IsNullOrWhiteSpace(expectedFrom) ? null : expectedFrom.Trim().ToLowerInvariant();
+        var normalizedExpectedFrom = await NormalizeActorAsync(expectedFrom, ct);
         var task = await CreateDashboardTaskAsync(title, detail, source, priority, assignedTo, parentTaskId, ct);
 
         task.IsAgentTask = true;
         task.ExpectedFrom = normalizedExpectedFrom;
-        task.State = TaskStateHelper.ToStateString(TaskState.InProgress);
+        task.State = ResolveInitialAgentTaskState(startsInProgress, initialState);
         await taskRepo.UpdateAsync(task, ct);
 
         await activityRepo.AddAsync(new ActivityEvent
@@ -322,7 +315,7 @@ public sealed class TaskService(
         }
         if (assignedTo is not null)
         {
-            var validated = ValidateAssignedTo(assignedTo);
+            var validated = await NormalizeActorAsync(assignedTo, ct);
             if (!string.Equals(task.AssignedTo ?? "", validated ?? "", StringComparison.OrdinalIgnoreCase))
             {
                 changes.Add($"Zuständig: {task.AssignedTo ?? "niemand"} → {validated ?? "niemand"}");
@@ -373,12 +366,24 @@ public sealed class TaskService(
             return new TaskOperationResult(TaskOperationOutcome.InvalidState);
 
         var canonical = TaskStateHelper.AllStates.First(s => s.Equals(status, StringComparison.OrdinalIgnoreCase));
-        task.State = canonical;
-        await taskRepo.UpdateAsync(task, ct);
-        await activityRepo.AddAsync(new ActivityEvent { Type = "task", Message = $"Task \"{task.Title}\" → {canonical}", TaskId = task.Id }, ct);
-        await CreateStatusChangeNotificationsAsync(task, canonical, ct);
-        await PublishBoardSnapshotAsync(ct);
-        return new TaskOperationResult(TaskOperationOutcome.Success, task);
+        return await UpdateTaskStatusInternalAsync(task, canonical, caller, "task", null, ct);
+    }
+
+    public async Task<TaskOperationResult> StartCoordinationAsync(Guid id, CancellationToken ct = default)
+    {
+        var task = await taskRepo.GetByIdAsync(id, ct);
+        if (task is null) return new TaskOperationResult(TaskOperationOutcome.NotFound);
+
+        if (!string.Equals(task.State, "Backlog", StringComparison.OrdinalIgnoreCase))
+            return new TaskOperationResult(TaskOperationOutcome.Success, task);
+
+        return await UpdateTaskStatusInternalAsync(
+            task,
+            canonical: TaskStateHelper.ToStateString(TaskState.InProgress),
+            actor: "nexus-system",
+            activityType: "delegation",
+            activityMessage: $"Task \"{task.Title}\" → In progress (coordination started by child-task creation)",
+            ct: ct);
     }
 
     public async Task<TaskOperationResult> CompleteViaQueueAsync(Guid id, CancellationToken ct = default)
@@ -481,12 +486,7 @@ public sealed class TaskService(
         if (!TaskStateHelper.CanChangeState(caller, task))
             return new TaskOperationResult(TaskOperationOutcome.InvalidState);
 
-        task.State = canonical;
-        await taskRepo.UpdateAsync(task, ct);
-        await activityRepo.AddAsync(new ActivityEvent { Type = "task", Message = $"Task \"{task.Title}\" moved to {canonical}", TaskId = task.Id }, ct);
-        await CreateStatusChangeNotificationsAsync(task, canonical, ct);
-        await PublishBoardSnapshotAsync(ct);
-        return new TaskOperationResult(TaskOperationOutcome.Success, task);
+        return await UpdateTaskStatusInternalAsync(task, canonical, caller, "task", $"Task \"{task.Title}\" moved to {canonical}", ct);
     }
 
     public Task<int> ResetStaleAsync(int staleHours, CancellationToken ct = default)
@@ -577,11 +577,25 @@ public sealed class TaskService(
             t.ParentTaskId.HasValue || t.IsAgentTask);
     }
 
-    private static string? ValidateAssignedTo(string? assignedTo)
+    private async Task<string?> NormalizeActorAsync(string? actorId, CancellationToken ct)
     {
-        if (string.IsNullOrWhiteSpace(assignedTo)) return null;
-        var lower = assignedTo.Trim().ToLowerInvariant();
-        return ValidAssignees.Contains(lower) ? lower : null;
+        var allowedActors = AgentIdentityCatalog.BuildAllowedActorIds(await agentService.GetAllowedAgentIdsAsync(ct));
+        return AgentIdentityCatalog.NormalizeActorId(actorId, allowedActors);
+    }
+
+    private static string ResolveInitialAgentTaskState(bool startsInProgress, string? initialState)
+    {
+        if (!string.IsNullOrWhiteSpace(initialState))
+        {
+            var canonical = TaskStateHelper.AllStates.FirstOrDefault(state =>
+                state.Equals(initialState, StringComparison.OrdinalIgnoreCase));
+            if (canonical is not null)
+                return canonical;
+        }
+
+        return startsInProgress
+            ? TaskStateHelper.ToStateString(TaskState.InProgress)
+            : TaskStateHelper.ToStateString(TaskState.Backlog);
     }
 
     private string ResolveCaller()
@@ -598,10 +612,29 @@ public sealed class TaskService(
         return nameClaim?.ToLowerInvariant() ?? "";
     }
 
-    private async Task CreateStatusChangeNotificationsAsync(WorkTask task, string canonical, CancellationToken ct)
+    private async Task<TaskOperationResult> UpdateTaskStatusInternalAsync(
+        WorkTask task,
+        string canonical,
+        string actor,
+        string activityType,
+        string? activityMessage,
+        CancellationToken ct)
     {
-        var caller = ResolveCaller();
+        task.State = canonical;
+        await taskRepo.UpdateAsync(task, ct);
+        await activityRepo.AddAsync(new ActivityEvent
+        {
+            Type = activityType,
+            Message = activityMessage ?? $"Task \"{task.Title}\" → {canonical}",
+            TaskId = task.Id
+        }, ct);
+        await CreateStatusChangeNotificationsAsync(task, canonical, actor, ct);
+        await PublishBoardSnapshotAsync(ct);
+        return new TaskOperationResult(TaskOperationOutcome.Success, task);
+    }
 
+    private async Task CreateStatusChangeNotificationsAsync(WorkTask task, string canonical, string caller, CancellationToken ct)
+    {
         if (string.Equals(canonical, "Review", StringComparison.OrdinalIgnoreCase))
         {
             await notificationService.CreateAsync(