revert: "build: Migrate to Vite 🚀" (#6814)

Revert "build: Migrate to Vite 🚀 (#6713)"

This reverts commit e93bbc5776.

src/i18n.ts

@@ -1,5 +1,6 @@
 import fallbackLangData from "./locales/en.json";
 import percentages from "./locales/percentages.json";
+import { ENV } from "./constants";
 import { jotaiScope, jotaiStore } from "./jotai";
 import { atom, useAtomValue } from "jotai";
 import { NestedKeyOf } from "./utility-types";
@@ -73,7 +74,7 @@ export const languages: Language[] = [
 ];
 
 const TEST_LANG_CODE = "__test__";
-if (import.meta.env.DEV) {
+if (process.env.NODE_ENV === ENV.DEVELOPMENT) {
   languages.unshift(
     { code: TEST_LANG_CODE, label: "test language" },
     {
@@ -144,7 +145,7 @@ export const t = (
   if (translation === undefined) {
     const errorMessage = `Can't find translation for ${path}`;
     // in production, don't blow up the app on a missing translation key
-    if (import.meta.env.PROD) {
+    if (process.env.NODE_ENV === "production") {
       console.warn(errorMessage);
       return "";
     }