fix(tools): fix cron_test build error and add TTL clone test

- Fix cron_test.go:229 — replace non-existent SubscribeOutbound(ctx)
  with select on OutboundChan(), matching the MessageBus channel API
- Add TestToolRegistry_Clone_PreservesTTLValue per reviewer feedback
- Add version reset note to Clone() doc comment

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

pkg/tools/cron_test.go

@@ -226,11 +226,12 @@ func TestCronTool_ExecuteJobPublishesErrorWhenExecDisabled(t *testing.T) {
 	ctx, cancel := context.WithTimeout(context.Background(), time.Second)
 	defer cancel()
 
-	msg, ok := tool.msgBus.SubscribeOutbound(ctx)
-	if !ok {
-		t.Fatal("expected outbound message")
-	}
-	if !strings.Contains(msg.Content, "command execution is disabled") {
-		t.Fatalf("expected exec disabled message, got: %s", msg.Content)
+	select {
+	case msg := <-tool.msgBus.OutboundChan():
+		if !strings.Contains(msg.Content, "command execution is disabled") {
+			t.Fatalf("expected exec disabled message, got: %s", msg.Content)
+		}
+	case <-ctx.Done():
+		t.Fatal("timeout waiting for outbound message")
 	}
 }

pkg/tools/registry.go

@@ -308,6 +308,7 @@ func (r *ToolRegistry) List() []string {
 // snapshot of the parent agent's tools without sharing the same registry —
 // tools registered on the parent after cloning (e.g. spawn, spawn_status)
 // will NOT be visible to the clone, preventing recursive subagent spawning.
+// The version counter is reset to 0 in the clone as it's a new independent registry.
 func (r *ToolRegistry) Clone() *ToolRegistry {
 	r.mu.RLock()
 	defer r.mu.RUnlock()

pkg/tools/registry_test.go

@@ -400,6 +400,31 @@ func TestToolRegistry_Clone_PreservesHiddenToolState(t *testing.T) {
 	}
 }
 
+func TestToolRegistry_Clone_PreservesTTLValue(t *testing.T) {
+	r := NewToolRegistry()
+	r.RegisterHidden(newMockTool("ttl_tool", "tool with TTL"))
+
+	// Manually set a non-zero TTL on the entry
+	r.mu.RLock()
+	if entry, ok := r.tools["ttl_tool"]; ok {
+		entry.TTL = 5
+	}
+	r.mu.RUnlock()
+
+	clone := r.Clone()
+
+	// Verify TTL value is preserved in the clone
+	clone.mu.RLock()
+	defer clone.mu.RUnlock()
+	entry, ok := clone.tools["ttl_tool"]
+	if !ok {
+		t.Fatal("expected ttl_tool to exist in clone")
+	}
+	if entry.TTL != 5 {
+		t.Errorf("expected TTL=5 in clone, got %d", entry.TTL)
+	}
+}
+
 func TestToolRegistry_ConcurrentAccess(t *testing.T) {
 	r := NewToolRegistry()
 	var wg sync.WaitGroup