Attach the bill to an existing work order (the app's Attach modal)

Each line item becomes a line on the work order with the defaults the modal proposes (title, amount, markup). work_order_item_id attaches it to a line already on the work order instead (e.g. a cost the task system recorded), whose description gains the line item's in parentheses. Leave line_items out to attach what the modal pre-checks: the line items on the work order's property. Attaching moves each one to the work order's property, so list one on another property to attach it anyway. work_order_id must be one the modal offers: open, recent, and linked to a task where the account attaches to task-management work orders.

sync picks the modal's button: task_integration_only is "Save to <task system> only"; left out, it's the main button. meta.sync says where the work order went, pushed in the background: task_integration, pms, or needs_review — the PMS needs fields only the work order form collects, so it's left in draft and meta.review_url opens it in the app. Needs permission to edit both the bill and the work order.