Agent Skills: paywall-upgrade-cro

When the user wants to optimize in-app paywalls, upgrade screens, or upgrade prompts -- including feature locks, usage limit walls, trial expiration screens, or context-triggered upsells. Also use when the user says "paywall design," "upgrade conversion," "upgrade modal," or "upsell prompt." For feature gating strategy, see feature-gating. For in-product messaging, see in-product-messaging.