Add authentication pages: create auth and signin components with layout and form handling

app/pages/auth.vue

@@ -0,0 +1,32 @@
+<script setup lang="ts">
+definePageMeta({
+	layout: false,
+})
+</script>
+
+<template>
+	<section class="auth">
+		<Card class="card">
+			<NuxtPage />
+		</Card>
+	</section>
+</template>
+
+<style lang="scss" scoped>
+@use "@/styles/variables" as *;
+
+.auth {
+	width: 100vw;
+	height: 100vh;
+	background-color: $color-background;
+
+	display: flex;
+	justify-content: center;
+	align-items: center;
+}
+
+.card {
+	width: 40%;
+	max-width: 450px;
+}
+</style>