Migration generators inconsistently specify version

[jeffhorn-nava]

Problem

Two of three Strata migration generators hard-code ActiveRecord::Migration[7.2]. The third (task) already interrogates ActiveRecord::Migration.current_version. Strata consumers on a newer Rails version inherit the wrong specifier from the two outdated templates.

Surfaced in oscer#570 (audit_log template produced [7.2] against OSCER on Rails 8.0).

Current state

Generator	Template	Status
task	lib/generators/strata/task/templates/create_strata_tasks.rb.tt	✅ uses current_version
determination	lib/generators/strata/determination/templates/create_strata_determinations.rb.tt	❌ hard-codes [7.2]
audit_log	lib/generators/strata/audit_log/templates/create_strata_audit_lines.rb.tt	❌ hard-codes [7.2]

Fix

Bring determination and audit_log into line with task: replace [7.2] with [<%= ActiveRecord::Migration.current_version %>].