API-only service for contracts, invoices, and payments.
GET /api/health — Health checkGET /api/v1/contracts — List contractsPOST /api/v1/contracts — Create contractGET /api/v1/invoices — List invoicesPOST /api/v1/invoices — Create invoiceGET /api/v1/payments — List paymentsPOST /api/v1/payments — Create paymentGET /api/v1/categories — List internal categoriesPOST /api/webhooks/stripe — Stripe webhook