Add ZarinPal e-payment and related checkout/search fixes.

Business settings can store ZarinPal merchant credentials, and the payment registry can initiate and verify ZarinPal alongside Mellat.

Co-authored-by: Cursor <cursoragent@cursor.com>

src/website-docs/static/AI_PROMPT.md

@@ -31,10 +31,10 @@ You are building a **Meshkee business website (storefront)**. You must use the M
 ### Typical bootstrap sequence
 1. `GET /tenants/{domain}` → branding + `businessId`
 2. Homepage: business-info, sliders, category-groups, brand-groups, store-specials
-3. Catalog: categories, products, store-items, **user-products** (customer stock listings)
+3. Catalog: categories, products, store-items (`name` instant search: in-stock first, then `updatedAt`), **user-products** (customer stock listings)
 4. Auth: register/login → store tokens. Optional: `POST /auth/send-otp` then `POST /auth/login-otp` (passwordless) or `POST /auth/reset-password` (forgot password). `POST /auth/verify-otp` only marks the cell verified (no tokens).
 5. Cart checkout with `addressId` or inline `shippingAddress` + `payment`
-   - For online pay: `payment.type = "e_payment_gate"`, `gatewayType` (e.g. `"mellat"`), and absolute `returnUrl`
+   - For online pay: `payment.type = "e_payment_gate"`, `gatewayType` (e.g. `"mellat"` or `"zarinpal"`), and absolute `returnUrl`
    - Response includes `payment.redirect` `{ method, url, fields }` — POST/redirect shopper to the bank
    - Bank callback hits API then redirects to `returnUrl?status=success|failed&orderId=…`
    - Enabled gateways: `GET /tenants/{domain}` → `ePayment`, or `GET /businesses/{businessId}/payments/methods`