- Add buildAppSnackBar in app_toast.dart so screen-tied SnackBars share the same per-ToastType icon/color scheme as showAppToast.
- Refactor toast visual resolution into a shared _resolveToastVisuals helper used by both SnackBars and toasts.
- Migrate ad-hoc SnackBar constructions across custom_errors, github, bulk_add_widget, themes_settings_section, ui_widgets, apps, and settings to use buildAppSnackBar with appropriate ToastType.
- Preserve SnackBar-specific behavior such as actions, persist, and duration while applying consistent theming.