fonde-ui

Add a new Fonde UI widget — implement under lib/src/widgets, export from lib/fonde_ui.dart, register a catalog page in the example app, and update README. Use when adding or scaffolding a new component.

Add or change a localized string in Fonde UI. l10n is managed manually (no intl, no flutter gen-l10n) — edit the .arb files plus the abstract class and the en/ja implementations by hand. Use when adding, renaming, or editing user-facing strings.