chore: New js transpiler for dev and for production

The old system weren't minifying javascriptt to assets dir.
Now there is a command line for production (build) and dev (build:dev).

app/javascript/controllers/shadcn_test_controller.js

@@ -1,7 +1,7 @@
 import { Controller } from "@hotwired/stimulus"
 import React from "react"
 import { createRoot } from "react-dom/client"
-import { Button } from "@/components/ui/button"
+import { Button } from "@/components/button"
 
 // Connects to data-controller="shadcn-test"
 export default class extends Controller {