Introduce client-side routing and cast API support. Key changes:
- Add react-router-dom dependency and wire BrowserRouter in App.
- Convert App to route-based structure (/, /media/:id, /cast, /cast/:id, /add, /import) with MediaDetailRoute and CastDetailRoute helpers.
- Extend API types for cast items and add convertApiCastToStaff; fetchAllCast now returns Staff[] (mapped via converter).
- Update components to use react-router hooks (useNavigate, useParams, useLocation, Link/NavLink): Header links, DetailView, CastDetailView, AddMediaView, ImporterView and others now navigate via routes.
- Enhance CastView: fetch cast list, loading state, persistent search/sort/filter controls, filtering by occupations/media types and enabled categories, improved pagination and UI controls.
- Update stashapp importer: add configurable blacklist check to skip scenes, increase per_page for queries.
These changes consolidate navigation, improve cast data handling from the API, and add richer filtering and importer controls.
