feat: localisation and multi-lang support (#95)

* feat: setup localisation with lingui

* Fix hydration and locale issues

* Add missing translations and tweak selector styling

* Extend language support

* Update lang support

* Extend lang support

* Fix build and add dyanmic imports

apps/web/src/utils/i18n.ts

@@ -0,0 +1,53 @@
+import { i18n } from "@lingui/core";
+
+import type { Locale } from "~/locales";
+import { defaultLocale } from "~/locales";
+import { messages as enMessages } from "~/locales/en/messages";
+
+const loadMessages = async (locale: Locale) => {
+  switch (locale) {
+    case "en":
+      return enMessages;
+    case "fr":
+      return (await import("~/locales/fr/messages")).messages;
+    case "de":
+      return (await import("~/locales/de/messages")).messages;
+    case "es":
+      return (await import("~/locales/es/messages")).messages;
+    case "it":
+      return (await import("~/locales/it/messages")).messages;
+    case "nl":
+      return (await import("~/locales/nl/messages")).messages;
+    default:
+      return enMessages;
+  }
+};
+
+let isInitialized = false;
+const loadedLocales = new Set<string>();
+
+export function initializeI18n(locale: Locale = defaultLocale) {
+  if (!isInitialized) {
+    i18n.load(defaultLocale, enMessages);
+    i18n.activate(defaultLocale);
+    loadedLocales.add(defaultLocale);
+    isInitialized = true;
+  }
+
+  return i18n;
+}
+
+export async function activateLocale(locale: Locale) {
+  if (!loadedLocales.has(locale)) {
+    const messages = await loadMessages(locale);
+    i18n.load(locale, messages);
+    loadedLocales.add(locale);
+  }
+
+  i18n.activate(locale);
+  return i18n;
+}
+
+initializeI18n();
+
+export { i18n };