Major 4.0 (#380)

- Migrated to WXT
- Migrated to NPM
- Added Insert & copy action
- Added ESLint

entrypoints/popup/specials/Snow.tsx

@@ -0,0 +1,20 @@
+import { mergeClasses } from "@fluentui/react-components";
+import { SNOWFLAKES_NUM, useStyles } from "./Snow.styles";
+
+const Snow: React.FC = () =>
+{
+	const cls = useStyles();
+
+	if (![0, 11].includes(new Date().getMonth()))
+		return null;
+
+	return (
+		<div className={ cls.snow }>
+			{ [...Array(SNOWFLAKES_NUM)].map((_, i) =>
+				<div key={ i } className={ mergeClasses(cls.snowflake, cls[`snowflake-${i}`]) } />
+			) }
+		</div>
+	);
+};
+
+export default Snow;