JoomShopping Robokassa payment addon - Version 2.0.0

This branch supports Joomla 5 and 6. Requirements: JoomShopping 5.5.0 or later; PHP 8.1 or later for Joomla 5 and PHP 8.3 or later for Joomla 6. Joomla 4 is no longer supported.

Fixed payment method registration on a clean installation. Updates preserve existing payment settings, names and pricing.

Updated Russian and English settings labels and help text. Improved the display of Result URL, Success URL and Fail URL. The payment surcharge description is now optional: an empty value uses the standard description.

Added a signature algorithm selector: MD5, SHA-256 or SHA-512. Improved signature, amount, currency and order association checks. Repeated notifications and browser returns from Robokassa preserve the status of an order that has already been processed.

Improved receipt item totals to account for discounts, rounding, shipping, packaging and payment surcharges. Added a tax setting for the payment surcharge.

Added a configurable timeout for requests to Robokassa. Improved payment service response checks and error handling when starting a payment.

Diagnostics use the native JoomShopping log. Detailed events, duration and memory measurements, and optional administrator email notifications for payment initialization errors are available.