Reconcile dynamic_combo detail-dialog codegen drift

CurrencyDetailDialog.cpp (and likely other entities' detail dialogs using dynamic_combo fields) has drifted from ores.codegen/library/templates/ores.cpp.qt.detail_dialog_impl.org's current async-lookup-combo template: the template now passes Loading…=/=Failed to load placeholder text and a code-extractor lambda to the combo-population helper, and reads back the current value via findData()=/=setCurrentIndex() (storing the code as itemData) instead of setCurrentText(). Needs a review pass across all dynamic_combo entities to bring them in line with the current template, verifying each diff is additive/correct before applying (not a blind regenerate) since this changes combo value-matching semantics.

Found while regenerating currency's controller for the generic-HistoryDialog codegen task (Update ores.cpp.qt codegen templates for the generic HistoryDialog): compass codegen entity generate currency --address ores.cpp.qt --diff surfaced this as unrelated drift alongside the intended HistoryDialog wiring change. Left untouched in that task to keep its diff scoped; captured here so the drift gets a deliberate, reviewed fix rather than being silently pulled in by an unrelated regeneration.

• projects/ores.qt/refdata/src/CurrencyDetailDialog.cpp — the drifted file found first.
• projects/ores.codegen/library/templates/ores.cpp.qt.detail_dialog_impl.org — the current template.

• Update ores.cpp.qt codegen templates for the generic HistoryDialog