chore: 'uc stop' - make --timeout default explicit, update flag and long descriptions

cmd/uncloud/service/start.go

@@ -19,8 +19,11 @@ func NewStartCommand(groupID string) *cobra.Command {
 	cmd := &cobra.Command{
 		Use:   "start SERVICE [SERVICE...]",
 		Short: "Start one or more services.",
-		Long:  "Start one or more services.",
-		Args:  cobra.MinimumNArgs(1),
+		Long: `Start one or more previously stopped services.
+
+Starts all containers of the specified service(s) across all machines in the cluster.
+Services can be specified by name or ID.`,
+		Args: cobra.MinimumNArgs(1),
 		RunE: func(cmd *cobra.Command, args []string) error {
 			uncli := cmd.Context().Value("cli").(*cli.CLI)
 			opts.services = args