layer1: log namespace watcher startup summary

doc/thinking/2026-04-26-namespace-manager-step51.md

@@ -2,6 +2,21 @@
 
 ## Цель шага
 
+Закрыть observability gap между `prepared namespace manager` и runtime transition logs.
+
+## Что изменено
+
+1. `RunManagedNamespaceWatcher()` теперь пишет единый summary log после старта watcher-а.
+2. Добавлен unit test на startup logging path.
+
+## Почему это полезно
+
+- buildermgr, router и executor получают одинаковый startup debug signal без копипасты;
+- видно состояние manager-а в момент, когда watcher уже реально подключён;
+- runtime semantics не меняется.# 2026-04-26 — NamespaceManager rewrite, step 51
+
+## Цель шага
+
 Убрать из call sites повторение стандартного config для managed namespace watcher-а.
 
 ## Что меняем

pkg/utils/namespace_manager.go

@@ -133,6 +133,7 @@ func PrepareManagedNamespaceWatcher(ctx context.Context, logger *zap.Logger, con
 func RunManagedNamespaceWatcher(ctx context.Context, logger *zap.Logger, kubeClient kubernetes.Interface, mgr managerPkg.Interface, config ManagedNamespaceWatcherConfig) (NamespaceManager, error) {
 	manager, handlers, err := PrepareManagedNamespaceWatcher(ctx, logger, config)
 	StartManagedNamespaceWatcher(ctx, logger, config.Component, kubeClient, mgr, handlers)
+	LogNamespaceManagerSummary(logger, config.Component+": started namespace watcher", manager.Summary())
 	return manager, err
 }
 

pkg/utils/namespace_manager_test.go

@@ -515,6 +515,45 @@ func TestRunManagedNamespaceWatcher(t *testing.T) {
 	}
 }
 
+func TestRunManagedNamespaceWatcherLogsStartedSummary(t *testing.T) {
+	ctx, cancel := context.WithCancel(context.Background())
+	defer cancel()
+	router := &testNamespaceSubscriber{name: "router"}
+	core, logs := observer.New(zap.InfoLevel)
+	logger := zap.New(core)
+
+	_, err := RunManagedNamespaceWatcher(ctx, logger, k8sfake.NewSimpleClientset(), managerPkg.New(), ManagedNamespaceWatcherConfig{
+		Component:       "router.NSWatcher",
+		Namespaces:      []string{"tenant-a"},
+		RemovalStrategy: NamespaceRemovalStrategyTrackOnly,
+		Subscriber:      router,
+	})
+	if err != nil {
+		t.Fatalf("expected managed namespace watcher run success: %v", err)
+	}
+
+	entries := logs.FilterMessage("router.NSWatcher: started namespace watcher").AllUntimed()
+	if len(entries) != 1 {
+		t.Fatalf("expected one started-summary log entry, got %d", len(entries))
+	}
+	fields := entries[0].ContextMap()
+	if live, ok := fields["live_namespaces"].(int64); !ok || live != 1 {
+		t.Fatalf("expected started summary to report one live namespace, got %v", fields["live_namespaces"])
+	}
+	if active, ok := fields["has_active_namespaces"].(bool); !ok || !active {
+		t.Fatalf("expected started summary to report active namespaces")
+	}
+	if total, ok := fields["total_namespaces"].(int64); !ok || total != 1 {
+		t.Fatalf("expected started summary to report one total namespace, got %v", fields["total_namespaces"])
+	}
+	if got := fields["subscribers"]; got == nil || !reflect.DeepEqual(got, []interface{}{"router"}) && !reflect.DeepEqual(got, []string{"router"}) {
+		t.Fatalf("expected started summary to report router subscriber, got %v", got)
+	}
+	if got := fields["phase_counts"]; got == nil {
+		t.Fatalf("expected started summary to report phase counts")
+	}
+}
+
 func TestNewDefaultManagedNamespaceWatcherConfig(t *testing.T) {
 	resolver := DefaultNSResolver()
 	original := resolver.FissionResourceNS