Convert legacy UI5 JS app ➜ Fiori Elements V4 (annotation-first)

Generate a Fiori Elements V4 list-report + object-page app driven by @UI.* annotations on the RAP CDS projection. Backend annotations are derived from the legacy UI5 app's actual features (columns, search, sort, formatters, action buttons, tab structure) so the FE app reproduces the user-visible contract. Custom behavior FE templates can't express is wired via the extension API.

This skill is one of two parallel UI paths after the RAP backend lands. Pick this one if the target architecture is Fiori Elements V4 (annotation-driven; minimal custom code). Pick modernize-ui5-app.md instead if the target is freestyle TypeScript (custom controllers, manual binding). Both start from the same legacy JS app + the same V4 RAP service.