Add grid item size setting and UI

Introduce a persistent gridItemSize user setting (1-10) across the app. Updates include: types (UserSettings.gridItemSize), API mappings (grid_item_size in ApiSettingsItem, CreateSettingsInput, convertApiToSettings, convertSettingsToApi), default setting values, and the App handler (handleGridItemSizeChange) to save changes. UI additions: slider control in SettingsView, slider and value in BrowseView (with syncing to incoming API settings), passing the prop and change callback from App, and a mapping from slider values to responsive Tailwind grid column classes so the grid layout adapts to the chosen size. Also added syncing of itemsPerPage in BrowseView and CastView with API-loaded settings.

src/components/CastView.tsx

@@ -38,6 +38,13 @@ export default function CastView({ onPersonClick, enabledCategories, itemsPerPag
   const [itemsPerPage, setItemsPerPage] = useState(initialItemsPerPage);
   const [showFilters, setShowFilters] = useState(false);
 
+  // Sync itemsPerPage with prop when API settings are loaded
+  useEffect(() => {
+    if (initialItemsPerPage) {
+      setItemsPerPage(initialItemsPerPage);
+    }
+  }, [initialItemsPerPage]);
+
   // Persist filters and sorts
   useEffect(() => {
     localStorage.setItem('castSearchQuery', searchQuery);