Replaces six scattered "chore" literals across TaskEntity, ListEntity,
WorkerHub, ListsIslandViewModel, ListNavItemViewModel and the inline
commit type list in ListSettingsModalViewModel.
Replaces three scattered model lists (ListSettingsModalViewModel,
DetailsIslandViewModel, GeneralSettingsTabViewModel) and the hardcoded
planning model with a single source. Planning launcher now uses the
opus alias instead of pinning claude-opus-4-7.
