Extends @formula2 so it can be placed on a @manytoone field. Instead of embedding physical SQL aliases (as @formula(join=...) requires), a @formula2 expression uses logical bean paths — the required joins are derived automatically.

  Example
``
   // Before — physical SQL, brittle alias wiring:
   @formula(select = "coalesce(${ta}.some_bean_id, j1.some_bean_id)", join = PARENTS_JOIN)
   @manytoone EBasic effectiveBean;
```
```
   // After — logical paths, joins resolved automatically:
   @formula2("coalesce(someBean.id, parent.someBean.id)")
   @manytoone EBasic effectiveBean;
``
  The generated SQL is identical; the annotation is far more readable and maintainable.

  What changed

  Annotation parsing (AnnotationAssocOnes) — @formula2 on a @manytoone is now recognised and the expression parsed into a select fragment and a set of dependency join paths.

  Query tree building (SqlTreeBuilder) — three scenarios all handled correctly:

   - Fetched as a tree node — dependency joins are inserted before the formula2 join using addChildFirst
   - Partial parent fetch — dependency joins are registered even when the parent chunk only selects its ID column
   - Predicate-only (where clause, no fetch) — addFormula2JoinsFromPredicates runs before buildSelectChain so dependency join paths are populated before buildExtraJoins constructs the extra-join tree; IncludesDistiller uses addChildFirst to preserve ordering within the extra-join tree

  Init ordering (BeanDescriptorManager) — initFormula2Properties() moved to a dedicated pass 5, after all descriptors are fully initialised, so cross-descriptor path resolution (e.g. parent.parent.someBean.id) is always safe.

  SqlTreeNodeExtraJoin — gained addChildFirst() to match SqlTreeNodeBean, enabling formula2 dependency joins to be prepended ahead of the formula2 property join in the extra-join tree.

  Fixes

  Supersedes and resolves #2773 — the reported bug (wrong join ordering when combining fetch and where on a formula-joined field) is eliminated for ChildPerson.effectiveBean and ParentPerson.effectiveBean, which are now expressed as @formula2.

Co-authored-by: robin.bygrave <robin.bygrave@eroad.com>