use cobra for cli

delete pkg/runner and put funcs in task
add start command

cmd/survey/main.go

@@ -0,0 +1,17 @@
+package main
+
+import (
+	"context"
+	"log"
+
+	"github.com/charmbracelet/fang"
+)
+
+func main() {
+	ctx := context.Background()
+
+	if err := fang.Execute(ctx, rootCmd,
+		fang.WithColorSchemeFunc(fang.AnsiColorScheme)); err != nil {
+		log.Fatalf("Failed to execute command: %v\n", err)
+	}
+}