Update Sync

Updates a model sync's configuration. Updating a model sync is a **full replacement** of the sync's configuration. Every field in the request body is written to the sync; any field you omit is cleared or reset to its default value. To make a partial change — for example, toggling `active` or adjusting a single field mapping — fetch the current sync with [`GET /api/syncs/{id}`](../../../api-reference/model-sync/get), modify the fields you want to change, and send the complete object back in the update request. Updates to `active`, `schedule`, and `policies` take effect immediately. Changes to source fields, target configuration, filters, or field mappings take effect on the sync's next execution.