Add internationalization support with astro-i18next integration

- Implemented astro-i18next for multi-language support, including English, Dutch, and Italian.
- Configured default locale and language fallback settings.
- Defined routes for localized content in the configuration.
- Updated package.json and package-lock.json to include new dependencies for i18next and related plugins.

node_modules/tsm/config/index.d.ts

@@ -0,0 +1,22 @@
+import type { Loader, TransformOptions } from 'esbuild';
+
+export type Extension = `.${string}`;
+export type Options = TransformOptions;
+
+export type Config = {
+	[extn: Extension]: Options;
+}
+
+export type ConfigFile =
+	| { common?: Options; config?: Config; loaders?: never; [extn: Extension]: never }
+	| { common?: Options; loaders?: Loaders; config?: never; [extn: Extension]: never }
+	| { common?: Options; config?: never; loaders?: never; [extn: Extension]: Options }
+
+export type Loaders = {
+	[extn: Extension]: Loader;
+}
+
+/**
+ * TypeScript helper for writing `tsm.js` contents.
+ */
+export function define(contents: ConfigFile): ConfigFile;