Collection: support filtering by non-main-side relationship without ->id

[hrach]

Collection: support filtering by non-main-side relationship without ->id

When filtering by a relationship property that does not hold the FK column
(ONE_HAS_ONE non-main side, ONE_HAS_MANY, MANY_HAS_MANY), the ORM now
automatically joins the target table and compares against its primary key.

Previously, only the main side worked (e.g. m:1 or 1:1 isMain) because
the FK column lives in the current table. The non-main side would produce
invalid SQL referencing a non-existent column.

Example: findBy(['departure!=' => null]) on Alarm, where departure is a
non-main 1:1 relationship, now correctly emits a LEFT JOIN instead of
trying to use a non-existent column.

Closes #574

Collection: skip JOIN for main-side relationship->id

When the last token is the primary key of a main-side relationship
(MANY_HAS_ONE / ONE_HAS_ONE isMain), use the FK column directly instead
of joining the related table. E.g. author->id becomes author_id
without an unnecessary JOIN to the authors table.

[hrach]

This change is part of the following stack:

• Collection: support filtering by non-main-side relationship without ->id #818 ◀

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