Currently only manages the invoice's linked estimate (quote) — despite the generic name, no job/organization/property association is supported by this endpoint today.

The estimate_uid key must be present in the body: a valid estimate uid associates/replaces the link, null dissociates it. Omitting the key entirely returns 400. If the given estimate is already the one linked, this is a no-op (200, no data object). Otherwise it recomputes the invoice's payment_history/amount_paid/amount_due/invoice_status (merging in any uncollected estimate deposit) and updates both the newly- and previously-linked estimate's conversion state.