Version: 0.9.68.dev.260504

后端：
1. 阶段 3 notification 服务边界落地，新增 `cmd/notification`、`services/notification`、`gateway/notification`、`shared/contracts/notification` 和 notification port，按 userauth 同款最小手搓 zrpc 样板收口
2. notification outbox consumer、relay 和 retry loop 迁入独立服务入口，处理 `notification.feishu.requested`，gateway 改为通过 zrpc client 调用 notification
3. 清退旧单体 notification DAO/model/service/provider/runner 和 `service/events/notification_feishu.go`，旧实现不再作为活跃编译路径
4. 修复 outbox 路由归属、dispatch 启动扫描、Kafka topic 探测/投递超时、sending 租约恢复、毒消息 MarkDead 错误回传和 RPC timeout 边界
5. 同步调整 active-scheduler 触发通知事件、核心 outbox handler、MySQL 迁移边界和 notification 配置

文档：
1. 更新微服务迁移计划，将阶段 3 notification 标记为已完成，并明确下一阶段从 active-scheduler 开始

backend/cmd/notification/main.go

@@ -0,0 +1,77 @@
+package main
+
+import (
+	"context"
+	"log"
+	"os"
+	"os/signal"
+	"syscall"
+
+	"github.com/LoveLosita/smartflow/backend/bootstrap"
+	kafkabus "github.com/LoveLosita/smartflow/backend/infra/kafka"
+	outboxinfra "github.com/LoveLosita/smartflow/backend/infra/outbox"
+	notificationdao "github.com/LoveLosita/smartflow/backend/services/notification/dao"
+	notificationrpc "github.com/LoveLosita/smartflow/backend/services/notification/rpc"
+	notificationsv "github.com/LoveLosita/smartflow/backend/services/notification/sv"
+	"github.com/spf13/viper"
+)
+
+func main() {
+	if err := bootstrap.LoadConfig(); err != nil {
+		log.Fatalf("failed to load config: %v", err)
+	}
+
+	ctx, stop := signal.NotifyContext(context.Background(), os.Interrupt, syscall.SIGTERM)
+	defer stop()
+
+	db, err := notificationdao.OpenDBFromConfig()
+	if err != nil {
+		log.Fatalf("failed to connect notification database: %v", err)
+	}
+
+	channelDAO := notificationdao.NewChannelDAO(db)
+	recordDAO := notificationdao.NewRecordDAO(db)
+	svc, err := notificationsv.NewNotificationServiceWithFeishuWebhook(recordDAO, channelDAO, notificationsv.FeishuWebhookProviderOptions{
+		FrontendBaseURL: viper.GetString("notification.frontendBaseURL"),
+	}, notificationsv.ServiceOptions{})
+	if err != nil {
+		log.Fatalf("failed to initialize notification service: %v", err)
+	}
+
+	outboxRepo := outboxinfra.NewRepository(db)
+	eventBus, err := outboxinfra.NewEventBus(outboxRepo, kafkabus.LoadConfig())
+	if err != nil {
+		log.Fatalf("failed to initialize notification outbox bus: %v", err)
+	}
+	if eventBus != nil {
+		if err := notificationsv.RegisterFeishuRequestedHandler(eventBus, outboxRepo, svc); err != nil {
+			log.Fatalf("failed to register notification outbox handler: %v", err)
+		}
+		eventBus.Start(ctx)
+		defer eventBus.Close()
+		log.Println("Notification outbox consumer started")
+	} else {
+		log.Println("Notification outbox consumer is disabled")
+	}
+
+	svc.StartRetryLoop(ctx, viper.GetDuration("notification.retryScanEvery"), viper.GetInt("notification.retryBatchSize"))
+	log.Println("Notification retry scanner started")
+
+	server, listenOn, err := notificationrpc.NewServer(notificationrpc.ServerOptions{
+		ListenOn: viper.GetString("notification.rpc.listenOn"),
+		Timeout:  viper.GetDuration("notification.rpc.timeout"),
+		Service:  svc,
+	})
+	if err != nil {
+		log.Fatalf("failed to build notification zrpc server: %v", err)
+	}
+	defer server.Stop()
+
+	go func() {
+		log.Printf("notification zrpc service starting on %s", listenOn)
+		server.Start()
+	}()
+
+	<-ctx.Done()
+	log.Println("notification service stopping")
+}