[Refactor] (Huge Refactoring 2)

Consolidated all logic into category-specific files.
Renamed useTranslation from react-i18next to useI18n to avoid a name conflict with our own function.

locales/useI18n.js

@@ -0,0 +1,11 @@
+// To avoid a name conflict with our own `useTranslation` function,
+// rename the one from `react-i18next` to `useI18n`.
+// This is aliased via `vite.config.js`, so it can be imported using `@useI18n`.
+// Example:
+// import { useI18n } from "@useI18n";
+//
+// export const useTranslation = () => {
+//     const { t } = useI18n();
+//     ...
+// };
+export { useTranslation as useI18n } from "react-i18next";