Support Odoo 18 and 19 from the same addon

[orangebtc]

Odoo 19 replaces the notification hooks used by this addon, so the previous release could not reconcile payments there. This change supports Odoo 18 and 19 from the same addon and main branch, selecting each version's native lookup and processing pipeline while sharing MakePay reconciliation logic.

Use manifest version 1.1.0, which Odoo normalizes to 18.0.1.1.0 or 19.0.1.1.0. Preserve signed-webhook authentication and browser return behavior. Explicitly skip Odoo 19's generic amount comparison because MakePay lifecycle events can contain crypto settlement amounts rather than the original order currency. Fix checkout error translation when a returned link UID shadows Odoo's translation user lookup.

Validation:

• Python/XML validation and git diff --check passed.
• Odoo 19 fresh installation and all 17 checkout/webhook regression tests passed in the official Docker image with PostgreSQL 16.
• Odoo 18 upgrade from 18.0.1.0.1 and all 17 regression tests passed with PostgreSQL 16.
• Verified the Odoo 18 upgrade preserves provider credentials, the existing pending transaction, its hosted link URL/UID, and subsequent reconciliation.
• GitHub Actions now performs fresh installations and runs the same regression suite in both Odoo 18 and 19.

Hosted checkout creation is mocked in regression tests; no live customer payments were initiated.