v4928.1.5.39 — Odoo panel import + draft attachment selection hotfix

Hotfix read/write behavior unchanged except for draft/document selection persistence.

Fixes

Fixes opportunity Odoo panel error name 'engine' is not defined by importing DB engine/text explicitly.
Fixes SEND_PROFORMA draft revision/send validation where older persisted drafts showed an ORC selected in compact UI but posted no selected_document_ids.
Centralizes effective selected-document fallback in task UI endpoints so generate/save/revise/send use the same ORC/invoice default.
Keeps ClientFlow business rule: proforma = Jasmin ORC.* quotation document.