[FEATURE REQUEST] - Configurable lookup fields for filtered-query IN-clause pivots

[3SigmaTech]

Feature title
Configurable lookup fields for filtered-query IN-clause pivots.

Problem statement
When a child object has several parent lookups, the filtered-query
planner (_createFilteredQueries in MigrationJobTask.ts) emits one IN-clause
query per lookup whose referenced object is also a script task. For
example, an Offer_Line_Item__c with Parent_Offer__c, Product__c,
and Related_Product__c triggers three filtered SELECTs in
STAGE 2, even when only one of those lookups is a meaningful
record-scope driver. The extra queries pull in unrelated records and
inflate both runtime and the result set.

The existing excludedFields setting can drop a field entirely, but
that also removes it from the SELECT clause and prevents the value
from being migrated.

Proposed solution
Add two opt-in settings on ScriptObject:

• includedInClauseFields — strict allow-list of lookup field names
  permitted as pivots. When set, only these fields produce filtered
  queries.
• excludedFromInClauseFields — deny-list of lookup field names that
  must not be used as pivots. When both are configured, the deny-list
  subtracts from the allow-list.

Listed fields remain in SELECT and migrate normally; only the
planner's pivot selection is affected. Behaviour is unchanged when
neither setting is provided.

Expected user impact

• Reduces wasted Bulk/REST calls on objects with multiple parent
  lookups.
• Avoids pulling unrelated records into a migration scope without
  forcing users to lose lookup field data.
• Gives finer control over query planning without resorting to fully
  custom query overrides (which forfeit the auto-generated SELECT).

Configuration example (if applicable)

{
  "objectName": "Offer_Line_Item__c",
  "includedInClauseFields": ["Parent_Offer__c"]
}

After this, only WHERE Parent_Offer__c IN (...) is emitted; the
other two lookups still appear in the SELECT and resolve normally.

Alternatives considered

• excludedFields — drops the field from SELECT entirely, losing
  data on the target.
• Removing Product__c from the script's objects list — works as
  a side-effect (no parent task → no pivot), but only if Product
  records aren't part of the migration; brittle.
• Custom query — works but means hand-maintaining the SELECT field
  list and losing the auto-generated behaviour.

Additional context
I have a working implementation on a feature branch and am happy to
open a PR if the maintainers are interested. The change is contained
to ScriptObject.ts and _createFilteredQueries in
MigrationJobTask.ts; ~28 lines added.