Search for available shipping products based on package dimensions, weight, quantity, and country locations. Returns products from multiple carriers (DPD, InPost, DHL, FedEx, UPS, GLS, etc.) grouped by delivery time (fast, superfast, noon, morning, standard). Includes pricing, delivery times, available addons, and carrier details. IMPORTANT: Do NOT guess or assume country IDs. Always call get_countries first, find the matching country by name or ISO code, and use the value from its 'id' field as the country ID.