Complete Payment and Auth Integration PlanPublic

The user aimed to create a comprehensive plan file integrating full payment, authentication, and billing management features using Polar and Better Auth. The outcome was a fully implemented and verified solution covering checkout, upgrade flows, portal cancellation, and billing state synchronization, with all code cleaned up to match the existing style and verified for correctness. The integration now supports seamless user management of subscriptions and billing through the pricing page and dropdown controls.