OptionaldescriptionFree-text description, or null to clear.
OptionalexpiresLink expiry (epoch ms), or null to clear.
OptionalpausedLive/paused — a paused link won't accept payment.
Optionalredirecthttp(s) merchant return URL, or null to clear.
PATCH body for a checkout/invoice — every field optional. Omit a field to leave it unchanged; send
nullto CLEAR it (redirectUrl/expiresAt/description).