feat: Implement menu item and category management with Redis caching for restaurant data.

src/cache/cache.keys.ts

@@ -0,0 +1,7 @@
+export const keys = {
+  restaurantBySlug: (slug: string) => `restaurant:slug:${slug}`,
+  restaurantCategories: (restaurantId: string) => `restaurant:${restaurantId}:categories`,
+  restaurantItems: (restaurantId: string) => `restaurant:${restaurantId}:items`,
+  category: (categoryId: string) => `category:${categoryId}`,
+  item: (itemId: string) => `item:${itemId}`,
+};