Pool and Spa Market Size & Forecasts 2026-2035, By Segments (Usage, Product Type, Material Type, Pool Features, Spa Features), Growth Opportunities, Innovation Landscape, Regulatory Shifts, Strategic Regional Insights (U.S., Japan, China, South Korea, UK, Germany, France), and Competitive Dynamics (Pentair, Hayward Industries, Zodiac Pool Systems, Fluidra, Jandy)