build: add livereload in watch mode

rollup.config.js

@@ -3,6 +3,7 @@
 // SPDX-License-Identifier: MIT
 
 import copy from "@guanghechen/rollup-plugin-copy";
+import livereload from "rollup-plugin-livereload";
 import styles from "rollup-plugin-styles";
 import { swc } from "rollup-plugin-swc3";
 
@@ -25,6 +26,7 @@ const staticFiles = [
     "templates",
 ];
 const isProduction = process.env.NODE_ENV === "production";
+const isWatch = process.env.ROLLUP_WATCH === "true";
 
 /**
  * @type {import('rollup').RollupOptions}
@@ -74,6 +76,7 @@ const config = {
             ],
             verbose: true,
         }),
+        isWatch && livereload(distDirectory),
     ],
 };