POST /experimental/promo-codes/redeem

Redeems a promo code for the signed-in user into their default org, or the org they joined first when they have no default; the user does not choose. The response's org names the org that got the code's credits, which expire the code's validity days after now. Each code is redeemed once, and only before its redeem-by time; a user can redeem many codes, and an org can receive many. 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, 409 for a code already redeemed, 410 for a code past its redeem-by time, 422 when the user belongs to no org, 403 for an API key, and 502 when the code was claimed but the grant failed; the grant is retried within the hour.