feat: extract shop from mp/shop — initial libreshop/shop

Source moved verbatim from mp/shop/ on 2026-04-29; mp was the first
concrete adapter consuming the libreshop toolkit. Builds and publishes
git.librete.ch/libreshop/shop on every main / v* push via the standard
.gitea/workflows/build.yml shared across libreshop components.

components/Carousel.vue

@@ -0,0 +1,57 @@
+<template>
+	<div class="carousel__wrapper">
+		<Carousel v-bind="carouselSettings">
+			<slot />
+			<template #addons>
+				<Navigation />
+			</template>
+		</Carousel>
+	</div>
+</template>
+
+<script setup>
+import "vue3-carousel/dist/carousel.css";
+import { Carousel, Navigation } from "vue3-carousel";
+
+const carouselSettings = {
+	itemsToShow: 1,
+	wrapAround: false,
+	transition: 360,
+	autoplay: false,
+	gap: 20,
+	mouseDrag: false,
+	touchDrag: true,
+	breakpoints: {
+		990: {
+			mouseDrag: false,
+			touchDrag: true,
+			itemsToShow: 4,
+			snapAlign: "start",
+			gap: 40,
+			pauseAutoplayOnHover: true
+		}
+	}
+};
+</script>
+
+<style>
+.carousel__prev,
+.carousel__next {
+	@apply w-24 h-24 absolute right-auto bottom-0 top-auto rounded-full hover:shadow-sm hover:bg-gray-100 focus:bg-gray-100 focus:ring-4 ring-gray-500 focus:ring-offset-2 bg-gray-200 bg-opacity-70 text-gray-400 text-sm transition-colors scale-75 font-bold;
+	left: min(7rem, calc(100% - 6rem));
+}
+
+.carousel__prev {
+	@apply left-0;
+}
+
+.carousel__viewport {
+	@apply overflow-hidden;
+}
+
+.carousel__wrapper {
+	.carousel__viewport {
+		@apply pb-28;
+	}
+}
+</style>