Hot Tub Market Size, Share & Industry Analysis, By Type (Portable Tubs, In-Ground/Fixed Tubs, Inflatable Tubs, and Swim Spas Tubs), By Technology (Standard Tubs and Smart Tubs), By End-User (Residential, Hotels & Resorts, Spas, Gyms, and Others), By Distribution Channel (Retail Stores/Showrooms, Direct-to-Consumer (D2C), Online Channels, and Others), and Regional Forecast, 2026-2034