Refactor the application initialization and data fetching strategy to improve performance, reliability, and user experience, especially within the Flutter webview context.
Key changes:
- **Bootstrap & Initialization**: Implemented a `beforeInteractive` bootstrap script to handle locale correction and safe-area insets before the app becomes visible, reducing layout shift and flickering.
- **Locale Routing**: Enhanced the middleware proxy to prioritize authoritative cookie-based locales and improved `Accept-Language` header parsing to support complex device headers.
- **Assessment Progress**: Introduced a local assessment progress tracking mechanism that merges server-side completion data with local `localStorage` drafts, ensuring users don't lose progress during transitions.
- **Data Fetching**: Optimized React Query configurations by increasing `staleTime` and disabling aggressive refetching on window focus/mount to reduce unnecessary network overhead.
- **UI/UX Improvements**:
- Replaced `next/image` icon loading with an inline `UiIcon` component to eliminate per-icon network requests and ensure icons are available in the initial HTML.
- Implemented a Flutter-style skeleton shimmer animation using CSS transforms for smoother performance in the webview.
- Updated CSS variables to use `env(safe-area-inset-*)` for better mobile compatibility.
- **Refactoring**:
- Consolidated marriage-related data fetching into a unified `useFormSchemaQuery` pattern.
- Simplified component logic by removing redundant `silent-reloader` calls and manual cache-busting headers.
- Improved type safety for the Flutter bridge and window global objects.
