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/PageSection.vue

@@ -0,0 +1,51 @@
+<template>
+	<section class="py-12 lg:py-16" :class="bgClass">
+		<div class="xl:container mx-auto px-6">
+			<h2 v-if="title" class="text-2xl lg:text-3xl font-bold mb-6">{{ title }}</h2>
+			<div class="prose prose-lg max-w-none" v-html="renderedContent"></div>
+		</div>
+	</section>
+</template>
+
+<script setup lang="ts">
+import { marked } from "marked";
+
+const props = defineProps<{
+	title?: string;
+	content: string;
+	variant?: "white" | "gray";
+}>();
+
+const renderedContent = computed(() => marked(props.content));
+const bgClass = computed(() => (props.variant === "gray" ? "bg-gray-50" : "bg-white"));
+</script>
+
+<style scoped>
+.prose :deep(p) {
+	@apply mb-4;
+}
+
+.prose :deep(strong) {
+	@apply font-semibold;
+}
+
+.prose :deep(a) {
+	@apply text-gray-900 underline underline-offset-2 hover:text-gray-600;
+}
+
+.prose :deep(ul) {
+	@apply list-disc pl-6 mb-4;
+}
+
+.prose :deep(ol) {
+	@apply list-decimal pl-6 mb-4;
+}
+
+.prose :deep(h2) {
+	@apply text-2xl font-bold mt-8 mb-4;
+}
+
+.prose :deep(h3) {
+	@apply text-xl font-semibold mt-6 mb-3;
+}
+</style>