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/cache.ts

@@ -294,13 +294,10 @@ process.on('SIGINT', () => {
  */
 export async function invalidateRecipeCaches(): Promise<void> {
 	try {
-		// Clear all recipe-related caches in parallel
+		// Clear all recipe-related caches for both languages in parallel
 		await Promise.all([
-			cache.del('recipes:all_brief'),
-			cache.delPattern('recipes:tag:*'),
-			cache.delPattern('recipes:in_season:*'),
-			cache.delPattern('recipes:category:*'),
-			cache.delPattern('recipes:icon:*'),
+			cache.delPattern('recipes:rezepte:*'),
+			cache.delPattern('recipes:recipes:*'),
 		]);
 	} catch (err) {
 		console.error('[Cache] Error invalidating recipe caches:', err);