refactor(pipeline): ввести Runner интерфейс

Ultraworked with [Sisyphus](https://github.com/code-yeongyu/oh-my-openagent)

Co-authored-by: Sisyphus <clio-agent@sisyphuslabs.ai>

cmd/synapse-backupper/backup.go

@@ -35,17 +35,7 @@ var (
 	outputWriter  io.Writer = os.Stderr
 )
 
-type pipelineRunner interface {
-	Run(
-		ctx context.Context,
-		pgDumpOpts pgdump.Options,
-		recipients []crypto.RecipientPub,
-		sink domain.Sink,
-		rand io.Reader,
-	) error
-}
-
-func defaultNewRunner(options ...pipeline.Option) pipelineRunner {
+func defaultNewRunner(options ...pipeline.Option) pipeline.Runner {
 	return pipeline.NewRunner(options...)
 }
 
@@ -91,7 +81,8 @@ var backupCmd = &cobra.Command{
 			return fmt.Errorf("load classical public key: %w", err)
 		}
 
-		recipients := []crypto.RecipientPub{pqPub, classicalPub}
+		recipients := make([]crypto.RecipientPub, 0, 2)
+		recipients = append(recipients, pqPub, classicalPub)
 
 		pgDumpOpts := pgdump.Options{
 			Host:          cfg.PG.Host,
@@ -110,7 +101,7 @@ var backupCmd = &cobra.Command{
 			slog.String("output_path", finalPath),
 		)
 
-		sink := newLocalSink(cfg.Backup.Dir)
+		var sink domain.Sink = newLocalSink(cfg.Backup.Dir)
 
 		registry := crypto.NewRegistry()
 		_ = registry.Register(0x0006, func() crypto.KEM { return mlkem768.New() })