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/tests/Aryx.AgentHost.Tests/CopilotAgentBundleTests.cs

@@ -53,6 +53,15 @@ public sealed class CopilotAgentBundleTests
         Assert.Equal(["glob", "view"], sessionConfig.AvailableTools);
     }
 
+    [Fact]
+    public void Constructor_StoresWhetherHooksAreConfigured()
+    {
+        CopilotAgentBundle bundle = new([], hasConfiguredHooks: true);
+
+        Assert.True(bundle.HasConfiguredHooks);
+        Assert.Empty(bundle.Agents);
+    }
+
     [Fact]
     public async Task CreateConfiguredSessionConfig_MergesInstructionsAndConvertsHandoffDeclarations()
     {

sidecar/tests/Aryx.AgentHost.Tests/CopilotTurnExecutionStateTests.cs

@@ -212,23 +212,7 @@ public sealed class CopilotTurnExecutionStateTests
         RunTurnCommandDto command = CreateCommand();
         CopilotTurnExecutionState state = new(command);
 
-        state.ObserveSessionEvent(
-            command.Pattern.Agents[0],
-            SessionEvent.FromJson(
-                """
-                {
-                  "type": "hook.start",
-                  "data": {
-                    "hookInvocationId": "hook-1",
-                    "hookType": "postToolUse",
-                    "input": {
-                      "toolName": "view"
-                    }
-                  },
-                  "id": "66666666-6666-6666-6666-666666666666",
-                  "timestamp": "2026-03-27T00:00:00Z"
-                }
-                """));
+        state.ObserveSessionEvent(command.Pattern.Agents[0], CreateHookStartEvent());
 
         HookLifecycleEventDto evt = Assert.Single(state.DrainPendingEvents().OfType<HookLifecycleEventDto>());
         Assert.Equal("start", evt.Phase);
@@ -237,6 +221,36 @@ public sealed class CopilotTurnExecutionStateTests
         Assert.NotNull(evt.Input);
     }
 
+    [Fact]
+    public void ObserveSessionEvent_HookEnd_QueuesHookLifecycleEvent()
+    {
+        RunTurnCommandDto command = CreateCommand();
+        CopilotTurnExecutionState state = new(command);
+
+        state.ObserveSessionEvent(command.Pattern.Agents[0], CreateHookEndEvent());
+
+        HookLifecycleEventDto evt = Assert.Single(state.DrainPendingEvents().OfType<HookLifecycleEventDto>());
+        Assert.Equal("end", evt.Phase);
+        Assert.Equal("postToolUse", evt.HookType);
+        Assert.Equal("hook-1", evt.HookInvocationId);
+        Assert.True(evt.Success);
+    }
+
+    [Fact]
+    public void ObserveSessionEvent_HookLifecycleEvents_AreSuppressedWhenConfigured()
+    {
+        RunTurnCommandDto command = CreateCommand();
+        CopilotTurnExecutionState state = new(command)
+        {
+            SuppressHookLifecycleEvents = true,
+        };
+
+        state.ObserveSessionEvent(command.Pattern.Agents[0], CreateHookStartEvent());
+        state.ObserveSessionEvent(command.Pattern.Agents[0], CreateHookEndEvent());
+
+        Assert.Empty(state.DrainPendingEvents());
+    }
+
     [Fact]
     public void ObserveSessionEvent_SessionCompactionComplete_QueuesCompactionEvent()
     {
@@ -295,6 +309,45 @@ public sealed class CopilotTurnExecutionStateTests
         Assert.Equal("agent-1", evt.AgentId);
     }
 
+    private static SessionEvent CreateHookStartEvent()
+    {
+        return SessionEvent.FromJson(
+            """
+            {
+              "type": "hook.start",
+              "data": {
+                "hookInvocationId": "hook-1",
+                "hookType": "postToolUse",
+                "input": {
+                  "toolName": "view"
+                }
+              },
+              "id": "66666666-6666-6666-6666-666666666666",
+              "timestamp": "2026-03-27T00:00:00Z"
+            }
+            """);
+    }
+
+    private static SessionEvent CreateHookEndEvent()
+    {
+        return SessionEvent.FromJson(
+            """
+            {
+              "type": "hook.end",
+              "data": {
+                "hookInvocationId": "hook-1",
+                "hookType": "postToolUse",
+                "success": true,
+                "output": {
+                  "status": "ok"
+                }
+              },
+              "id": "99999999-9999-9999-9999-999999999999",
+              "timestamp": "2026-03-27T00:00:00Z"
+            }
+            """);
+    }
+
     private static RunTurnCommandDto CreateCommand()
     {
         return new RunTurnCommandDto

sidecar/tests/Aryx.AgentHost.Tests/CopilotWorkflowRunnerTests.cs

@@ -11,6 +11,18 @@ namespace Aryx.AgentHost.Tests;
 
 public sealed class CopilotWorkflowRunnerTests
 {
+    [Fact]
+    public void ConfigureHookLifecycleEventSuppression_SetsStateFromBundle()
+    {
+        RunTurnCommandDto command = CreateApprovalCommand();
+        CopilotTurnExecutionState state = new(command);
+        CopilotAgentBundle bundle = new(Array.Empty<AIAgent>(), hasConfiguredHooks: false);
+
+        CopilotWorkflowRunner.ConfigureHookLifecycleEventSuppression(state, bundle);
+
+        Assert.True(state.SuppressHookLifecycleEvents);
+    }
+
     [Fact]
     public void SelectNewOutputMessages_SkipsFullTranscriptPrefix()
     {