Introduced IAppTitleService for platform-agnostic environment badge in the app title ("[PROD]" or "[DEV] FruitBank"), with implementations for Web (document.title), MAUI (window title), and server (no-op). Registered the service per platform in DI. MainLayout now updates the title reactively on environment changes via FruitBankConstClient.IsProdChanged. Improved event handling and prevented redundant environment hydration calls. No business logic affected; changes are UI/infrastructure only.
