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/utils/cmsApi.ts

@@ -0,0 +1,17 @@
+/**
+ * Server-side CMS API utility.
+ * Use this for direct CMS access during SSR.
+ */
+export async function fetchCms<T>(endpoint: string, options: Parameters<typeof $fetch>[1] = {}): Promise<T> {
+	const config = useRuntimeConfig();
+	const url = `${config.cmsInternalUrl}/api${endpoint}`;
+
+	return await $fetch<T>(url, {
+		...options,
+		headers: {
+			"Content-Type": "application/json",
+			Authorization: `Bearer ${config.shopApiToken}`,
+			...((options.headers as Record<string, string>) || {})
+		}
+	});
+}

server/utils/coverSlug.ts

@@ -0,0 +1,37 @@
+import { fetchCms } from "./cmsApi";
+
+export function slugify(text: string): string {
+	return text
+		.toLowerCase()
+		.replace(/\s+/g, "-")
+		.replace(/ü/g, "ue")
+		.replace(/ä/g, "ae")
+		.replace(/ö/g, "oe")
+		.replace(/ß/g, "ss");
+}
+
+/**
+ * Resolves a cover slug or ID to the actual cover ID.
+ * If the input is already a numeric ID, returns it as-is.
+ * If it's a slug, looks up the cover by name and returns the ID.
+ */
+export async function resolveCoverId(idOrSlug: string): Promise<string | null> {
+	// If it's already a numeric ID, return it
+	if (/^\d+$/.test(idOrSlug)) {
+		return idOrSlug;
+	}
+
+	// Otherwise, fetch all covers and find by slug
+	try {
+		const allCovers = await fetchCms<{ data: any[] }>(`/product-covers`);
+		const cover = allCovers.data?.find((c: any) => {
+			const name = c.attributes?.name || c.name;
+			const slug = slugify(name || "");
+			return slug === idOrSlug;
+		});
+
+		return cover?.id?.toString() || null;
+	} catch {
+		return null;
+	}
+}