7fb8b83810
- Add isValidReturnUrl validation at route level for fast rejection - Add defense-in-depth validation in BillingService.createCustomerPortalSession - Fix isValidReturnUrl bug: origin comparison was never reached due to incorrect protocol check, allowing substring attacks (e.g., app.shieldai.com.evil.com) - Export isValidReturnUrl from shared-billing package index - Add unit tests for all attack vectors Files changed: - packages/api/src/routes/subscription.routes.ts - packages/shared-billing/src/services/billing.service.ts - packages/shared-billing/src/config/billing.config.ts - packages/shared-billing/src/index.ts - packages/shared-billing/src/__tests__/billing.config.test.ts