Compare localized fields with the closest origin that carries the key

[SUXUMI]

Fixes #616

Entry::makeModelFromContract() compares local values with the root instead of the closest origin carrying the field. It checks __localized_fields in $fieldOrigin->data(), but fromModel() never adds that key, so the loop always reaches the root.

With three or more sites in an origin chain, this causes two errors:

• A local value matching the root but differing from the inherited value is dropped.
• A copy of the direct origin's value is marked as localized when the root differs, so it stops following its origin.

A null localized by the direct origin is also skipped.

The one-line fix uses ! $fieldOriginData->has($blueprintField) to stop at the closest origin carrying the field, including stored null, matching HasOrigin::value().

Two tests cover the dropped value and the unnecessary localization. Both fail on 5.x without the fix.