WIP: Spec for versioned field list bug - refs #665

[philayres]

WIP: Versioned field list spec for issue #665

Status: Work in Progress — awaiting a concrete reproduction scenario from the reporter.

What this PR contains

A spec file (spec/models/dynamic/versioned_field_list_spec.rb) that tests whether versioned dynamic model definitions correctly restrict fields to those that existed at the time a record was created.

Tests cover

• field_list_array on versioned definitions excludes new fields
• option_type_config fields on versioned definitions excludes new fields
• edit_form_field_list for old instances excludes new fields
• TemplateOptionMapping.dynamic_model_mapping item_list excludes new fields

Current findings

All 4 tests pass at the model layer, meaning the core versioning of field_list works correctly when an explicit field_list is set. The bug likely manifests in a different scenario (e.g. blank field_list auto-detected from table columns, or in the rendering/template layer).

Next steps

• Clarify the exact reproduction scenario from the issue reporter
• Write additional tests covering the specific failing case
• Implement the fix

Refs #665