feat: starting heijunka article

src/AppHeijunka.vue

@@ -0,0 +1,28 @@
+<script setup lang="ts">
+import { ref } from 'vue'
+
+const createdAt = new Date('2026-01-01').toLocaleDateString(undefined, {
+  year: 'numeric',
+  month: 'long',
+  day: 'numeric'
+})
+</script>
+
+<template>
+  <article id="main-app">
+    <h1>Heijunka</h1>
+    <h2 class="created-at numeric">
+      {{ createdAt }}
+    </h2>
+    <div class="text">
+      <p>You're selling shirts, jeans and shoes.</p>
+    </div>
+    <BoardGameWorkshop />
+  </article>
+</template>
+
+<style scoped lang="scss">
+main {
+  min-height: calc(100vh - 2 * 1rem);
+}
+</style>