refactor: merge api/recipes and api/rezepte into unified recipeLang route

Consolidate duplicate recipe API routes into a single
api/[recipeLang=recipeLang]/ structure. Both /api/recipes/ and
/api/rezepte/ URLs continue to work via the param matcher. Shared
read endpoints now serve both languages with caching for both.

Also: remove dead code (5 unused components, cookie.js) and the
redundant cron-execute recurring payment route.

src/lib/server/recipeHelpers.ts

@@ -0,0 +1,57 @@
+import type { BriefRecipeType } from '$types/types';
+
+/**
+ * Check whether a recipeLang param refers to the English version.
+ */
+export function isEnglish(recipeLang: string): boolean {
+	return recipeLang === 'recipes';
+}
+
+/**
+ * Build a MongoDB query filter and field selection for brief recipe lists,
+ * handling German (root fields) vs English (translations.en.*) transparently.
+ */
+export function briefQueryConfig(recipeLang: string) {
+	const en = isEnglish(recipeLang);
+	return {
+		/** Extra filter to merge into every query (approval check for English) */
+		approvalFilter: en ? { 'translations.en.translationStatus': 'approved' } : {},
+		/** Field path prefix for translated fields (category, tags, name, etc.) */
+		prefix: en ? 'translations.en.' : '',
+		/** Projection for brief list queries */
+		projection: en
+			? '_id translations.en short_name images season dateModified icon'
+			: 'name short_name images tags category icon description season dateModified',
+	};
+}
+
+/**
+ * Map a raw DB recipe document to the brief format used by the frontend.
+ * For English, extracts from translations.en and adds germanShortName.
+ * For German, passes through root-level fields.
+ */
+export function toBrief(recipe: any, recipeLang: string): BriefRecipeType {
+	if (isEnglish(recipeLang)) {
+		return {
+			_id: recipe._id,
+			name: recipe.translations.en.name,
+			short_name: recipe.translations.en.short_name,
+			images: recipe.images?.[0]
+				? [{ alt: recipe.images[0].alt, mediapath: recipe.images[0].mediapath }]
+				: [],
+			tags: recipe.translations.en.tags || [],
+			category: recipe.translations.en.category,
+			icon: recipe.icon,
+			description: recipe.translations.en.description,
+			season: recipe.season || [],
+			dateModified: recipe.dateModified,
+			germanShortName: recipe.short_name,
+		} as BriefRecipeType;
+	}
+	return {
+		...recipe,
+		images: recipe.images?.[0]
+			? [{ alt: recipe.images[0].alt, mediapath: recipe.images[0].mediapath }]
+			: [],
+	} as BriefRecipeType;
+}