momentjs guide and fix webpack babel loader

guides/momentjs.md

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+# Moment.js
+
+This guide shows you how to install and use Moment.js, a popular date library in ToonBoom Harmony.
+
+Install it from NPM and create a new script file:
+
+```sh
+❯ npm install moment
+❯ touch ./src/scripts/moment.ts
+```
+
+Use ES modules to import the library:
+
+```ts
+// src/scripts/moment.ts
+import moment from "moment";
+
+MessageLog.trace(moment().locale("es").format("LLLL"));
+```
+
+Build it:
+
+```sh
+❯ npm run build
+```
+
+Then run `dist/moment.js` in Harmony:
+
+```txt
+martes, 18 de noviembre de 2025 12:23
+```