Stripe Billing Integration

## Monetization Ready Three weeks after MVP, we added the billing layer. ### What's Included - **Stripe Checkout** — Seamless subscription signup flow - **Customer Portal** — Self-service billing management - **Subscription management** — Create, update, cancel subscriptions - **Payment methods** — Credit cards, with support for additional methods - **Usage tracking** — Message counts tied to plan limits - **Migrations** — Database schema for customers, subscriptions, payment methods ### Plans We designed a tiered pricing model from day one — Free, Starter, Pro, and Enterprise — each with different agent limits, message quotas, and feature access.