Get Payment Methods

Get available payment methods for the current user.

Uses PaymentMethodConfig from database for:

• Sort order (sort_order)
• Enabled/disabled status (is_enabled)
• Display names (display_name with fallback to env)
• Min/max amounts (with fallback to env defaults)
• Sub-options filtering (sub_options)
• User filters (user_type_filter, first_topup_filter, promo_group_filter)