fix(worker): DeleteTask aus der UI schlug immer mit generischem Serverfehler fehl

Der CancellationToken-Parameter auf der nicht-streamenden Hub-Methode liess SignalR jede Invocation vor dem Methodenrumpf abbrechen. Die Tests riefen den Hub direkt auf und sahen das nicht; neuer Reflection-Guard verbietet CancellationToken auf allen nicht-streamenden Hub-Methoden.

src/ClaudeDo.Worker/Hub/WorkerHub.cs

@@ -277,8 +277,11 @@ public sealed class WorkerHub : Microsoft.AspNetCore.SignalR.Hub
     // TryAdvanceParentAsync side effect — a direct-repo delete from the details pane
     // used to skip it, permanently wedging a WaitingForChildren parent whose last
     // child was deleted from there.
-    public async Task DeleteTask(string taskId, CancellationToken cancellationToken)
+    // No CancellationToken parameter: SignalR can't bind one on a non-streaming method and fails
+    // every invocation with a generic server error before the body runs.
+    public async Task DeleteTask(string taskId)
     {
+        var cancellationToken = CancellationToken.None;
         await using var ctx = await _dbFactory.CreateDbContextAsync(cancellationToken);
         var repo = new TaskRepository(ctx);
         var task = await repo.GetByIdAsync(taskId, cancellationToken)

tests/ClaudeDo.Worker.Tests/Hub/DeleteTaskHubTests.cs

@@ -66,7 +66,7 @@ public sealed class DeleteTaskHubTests : IDisposable
         var (parentId, childId) = await SeedParentWithChildAsync(TaskStatus.Idle);
         var hub = CreateHub();
 
-        await hub.DeleteTask(childId, default);
+        await hub.DeleteTask(childId);
 
         await using var ctx = _db.CreateContext();
         Assert.Null(await ctx.Tasks.FindAsync(childId));
@@ -80,7 +80,7 @@ public sealed class DeleteTaskHubTests : IDisposable
         var (_, childId) = await SeedParentWithChildAsync(TaskStatus.Running);
         var hub = CreateHub();
 
-        await Assert.ThrowsAsync<HubException>(() => hub.DeleteTask(childId, default));
+        await Assert.ThrowsAsync<HubException>(() => hub.DeleteTask(childId));
 
         await using var ctx = _db.CreateContext();
         Assert.NotNull(await ctx.Tasks.FindAsync(childId));
@@ -92,7 +92,7 @@ public sealed class DeleteTaskHubTests : IDisposable
         var (parentId, _) = await SeedParentWithChildAsync(TaskStatus.Idle);
         var hub = CreateHub();
 
-        var ex = await Assert.ThrowsAsync<HubException>(() => hub.DeleteTask(parentId, default));
+        var ex = await Assert.ThrowsAsync<HubException>(() => hub.DeleteTask(parentId));
 
         Assert.Contains("child tasks", ex.Message, StringComparison.OrdinalIgnoreCase);
     }
@@ -102,6 +102,22 @@ public sealed class DeleteTaskHubTests : IDisposable
     {
         var hub = CreateHub();
 
-        await Assert.ThrowsAsync<HubException>(() => hub.DeleteTask("does-not-exist", default));
+        await Assert.ThrowsAsync<HubException>(() => hub.DeleteTask("does-not-exist"));
+    }
+
+    /// <summary>A CancellationToken on a non-streaming hub method breaks SignalR binding (every call fails with a generic server error); direct-call tests can't see that.</summary>
+    [Fact]
+    public void NoNonStreamingHubMethod_TakesCancellationToken()
+    {
+        var offenders = typeof(WorkerHub)
+            .GetMethods(System.Reflection.BindingFlags.Public | System.Reflection.BindingFlags.Instance | System.Reflection.BindingFlags.DeclaredOnly)
+            .Where(m => !m.IsSpecialName)
+            .Where(m => !(m.ReturnType.IsGenericType && m.ReturnType.GetGenericTypeDefinition() is var g
+                          && (g == typeof(IAsyncEnumerable<>) || g == typeof(System.Threading.Channels.ChannelReader<>))))
+            .Where(m => m.GetParameters().Any(p => p.ParameterType == typeof(CancellationToken)))
+            .Select(m => m.Name)
+            .ToList();
+
+        Assert.Empty(offenders);
     }
 }