- identity: when FlatPay (broker) is configured, InitiateZarinPalAsync
routes through pay.flatrender.ir instead of calling ZarinPal directly;
new HandleBrokerCallbackAsync confirms the payment via the broker
inquiry API (authoritative, not trusting the redirect) and activates
the plan. New public endpoint GET /v1/payments/callback/broker
(already public at the gateway via /callback/*). Env-gated — empty
FlatPay__ApiKey keeps the legacy direct-ZarinPal path.
- broker: deliver webhooks inline on enqueue (best-effort) in addition
to the retry loop, so clients credit near-instantly (db.GetWebhook +
goroutine kick).
- compose + ENV_FILE: FlatPay__* for identity (FLATPAY_FLATRENDER_*).
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
soroush.asadi
376cdf6a1c