chore: upgrade i18next 26, prettier 3, fontsource-variable, domhandler 6, lint-staged 17

- i18next 23->26 + react-i18next 15->17
- prettier 2->3, reformat all files
- replace @fontsource/inter with @fontsource-variable/inter 5, update import path
- domhandler 5->6 (aligns with transitive deps)
- lint-staged 16->17

src/app/pages/auth/register/Register.tsx

@@ -20,7 +20,7 @@ const useRegisterSearchParams = (searchParams: URLSearchParams): RegisterPathSea
       email: searchParams.get('email') ?? undefined,
       token: searchParams.get('token') ?? undefined,
     }),
-    [searchParams]
+    [searchParams],
   );
 
 export function Register() {