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.

server/api/product-covers/[id].get.ts

@@ -0,0 +1,18 @@
+import { fetchCms } from "~/server/utils/cmsApi";
+import { resolveCoverId } from "~/server/utils/coverSlug";
+
+export default defineEventHandler(async (event) => {
+	const idOrSlug = getRouterParam(event, "id");
+	if (!idOrSlug) {
+		throw createError({ statusCode: 400, statusMessage: "Missing cover ID" });
+	}
+
+	// Resolve slug to ID
+	const coverId = await resolveCoverId(idOrSlug);
+
+	if (!coverId) {
+		throw createError({ statusCode: 404, statusMessage: "Cover not found" });
+	}
+
+	return await fetchCms(`/product-covers/${coverId}?populate[copyText]=true`);
+});