Callback

Deep Dive into Payment Webhook & Callback Handling — Optimistic Locking, Idempotency, Atomic Wallet Operations

In-depth analysis of PaymentWebhookController (single endpoint routing + callback-token authentication) → handleUniversalWebhook (deposit/withdrawal routing) → handleInvoiceWebhook (updateMany optimistic locking + creditCash) → handlePayoutWebhook (atomic unfreeze + CRITICAL degradation) → WalletService (ensureWallet / creditCash / freezeCash / unfreezeCash + beforeBalance/afterBalance audit trail)