GET /experimental/promo-codes/{code}

Looks up a promo code for the signed-in user: the credits it grants, how many days they last after redemption, the name shown on the grant, its redeem-by time, whether it can still be redeemed, and the org the user's redemption would grant to (their default org, or the org they joined first; null when they have none). It never says who redeemed it. Matching ignores case, and spaces and hyphens are the same. Lookups and redemptions share a per-user rate limit (429). Returns 404 for an unknown code, and 403 for an API key.