fix: suppress noisy hook lifecycle events

Stop forwarding hook lifecycle events when a project has no configured
.github/hooks/*.json commands so the UI only receives meaningful hook
activity. Also expose the configured-hook state on the bundle, cover the
suppression wiring with tests, and document the updated event semantics.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

sidecar/src/Aryx.AgentHost/Services/CopilotWorkflowRunner.cs

@@ -75,6 +75,7 @@ public sealed class CopilotWorkflowRunner : ITurnWorkflowRunner
                     }
                 },
                 runCancellation.Token);
+            ConfigureHookLifecycleEventSuppression(state, bundle);
             Workflow workflow = bundle.BuildWorkflow(command.Pattern);
             List<ChatMessage> inputMessages = command.Messages.Select(WorkflowTranscriptProjector.ToChatMessage).ToList();
             WorkflowTranscriptProjector.AttachMessageMode(inputMessages, command.MessageMode);
@@ -118,6 +119,16 @@ public sealed class CopilotWorkflowRunner : ITurnWorkflowRunner
         }
     }
 
+    internal static void ConfigureHookLifecycleEventSuppression(
+        CopilotTurnExecutionState state,
+        CopilotAgentBundle bundle)
+    {
+        ArgumentNullException.ThrowIfNull(state);
+        ArgumentNullException.ThrowIfNull(bundle);
+
+        state.SuppressHookLifecycleEvents = !bundle.HasConfiguredHooks;
+    }
+
     private static async Task EmitPendingEventsAsync(
         CopilotTurnExecutionState state,
         Func<SidecarEventDto, Task> onEvent)