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/Teaser.vue

@@ -0,0 +1,74 @@
+<template>
+	<section class="w-full relative overflow-hidden min-h-[16rem]" :style="backgroundStyle">
+		<div class="absolute inset-0 bg-gradient-to-b from-black/40 to-black/60"></div>
+
+		<div class="container mx-auto px-6 h-full flex flex-col items-center justify-between py-16 relative z-10">
+			<!-- Top content with heading and optional subheading -->
+			<div class="text-center mt-12 mb-8">
+				<h2 class="font-bebas text-4xl md:text-5xl lg:text-6xl text-white tracking-tight leading-none">
+					{{ title }}
+				</h2>
+				<p v-if="subtitle" class="mt-4 text-white/90 text-lg md:text-xl max-w-2xl mx-auto">
+					{{ subtitle }}
+				</p>
+
+				<!-- Button after title option -->
+				<div v-if="buttonPosition === 'after-title'" class="mt-8">
+					<NuxtLink
+						v-if="href"
+						:to="href"
+						class="bg-white text-gray-900 hover:bg-gray-200 hover:text-red-600 transition-colors px-8 py-3 rounded-full font-medium"
+					>
+						{{ buttonText }}
+					</NuxtLink>
+					<button
+						v-else
+						@click="$emit('button-click')"
+						class="bg-white text-gray-900 hover:bg-gray-200 hover:text-red-600 transition-colors px-8 py-3 rounded-full font-medium"
+					>
+						{{ buttonText }}
+					</button>
+				</div>
+			</div>
+
+			<!-- Bottom button option -->
+			<div v-if="buttonPosition === 'bottom'" class="mb-12">
+				<NuxtLink
+					v-if="href"
+					:to="href"
+					class="bg-white text-gray-900 hover:bg-gray-200 hover:text-red-600 transition-colors px-8 py-3 rounded-full font-medium"
+				>
+					{{ buttonText }}
+				</NuxtLink>
+				<button
+					v-else
+					@click="$emit('button-click')"
+					class="bg-white text-gray-900 hover:bg-gray-200 hover:text-red-600 transition-colors px-8 py-3 rounded-full font-medium"
+				>
+					{{ buttonText }}
+				</button>
+			</div>
+		</div>
+	</section>
+</template>
+
+<script setup lang="ts">
+const props = defineProps<{
+	backgroundImage: string;
+	title: string;
+	subtitle?: string;
+	buttonText?: string;
+	buttonPosition?: "bottom" | "after-title";
+	height?: string;
+	href?: string;
+}>();
+
+const emit = defineEmits(["button-click"]);
+
+const backgroundStyle = computed(() => ({
+	backgroundImage: `url('${props.backgroundImage}')`,
+	backgroundSize: "cover",
+	backgroundPosition: "center",
+	height: props.height || "70vh"
+}));
+</script>