refactor(bootstrap): move runtime init from router to cmd layer

Extract SyncEvents and InitLogWriter from router.Serve into bootstrap.Init
called from cmd entry points with trace-aware context. Preserve existing
Register* wiring for task and push domain integrations.

internal/cmd/api.go

@@ -5,6 +5,7 @@
 package cmd
 
 import (
+	"github.com/Rain-kl/Wavelet/internal/bootstrap"
 	"github.com/Rain-kl/Wavelet/internal/router"
 	"github.com/spf13/cobra"
 )
@@ -13,6 +14,8 @@ var apiCmd = &cobra.Command{
 	Use:   "api",
 	Short: "wavelet API",
 	Run: func(_ *cobra.Command, _ []string) {
+		bootstrap.RegisterAPI()
+		runBootstrap(bootstrap.Options{API: true})
 		router.Serve()
 	},
 }