Blended customer LTV across every connected Shopify store (server-side merge).

• Plan-gated: may return 403 FEATURE_GATED on lower plans.
• CACHED: this route wraps its live fetch in a short read-through response cache — 60s when the range includes today, 300s when the range is fully in the past.
• Entries always expire and re-fetch live; a fetch failure never falls back to a cached value.
• Polling faster than once a minute returns the identical body.
• Money fields are integer piasters (EGP x 100).