Multi-Cycle Coupon Support for Subscription Products

Current behavior: Coupon "Cycles" field customization only supports one subscription (one cycle/plan) per coupon code. Coupons cannot be applied across multiple subscription cycles of the same product.

Requested behavior: Allow a single coupon code (e.g., CHRISTMAS25) to apply a discount across all subscription cycles/plans of a given product — e.g., 1-month, 3-month, 6-month, and 12-month plans for a medication — rather than requiring a separate coupon per cycle.

Use case: One wants to offer one consistent discount code for a product line regardless of which subscription duration the customer selects, instead of creating and managing multiple single-cycle coupons.