Global Boxspring Market Size, Share & Demand Report By Product Type (Standard Boxspring, Low-Profile Boxspring, Adjustable Boxspring), By Material Type (Wooden Frame, Metal Frame, Upholstered), By Distribution Channel (Offline Retail, Online Retail), By Price Range (Budget, Mid-Range, Premium), By End-Use (Residential, Hospitality & Hotels, Healthcare & Wellness), By Region & Segment Forecasts, 2025–2030