broke up monolithic structure

frontend/js/state.js

@@ -0,0 +1,23 @@
+window.App = window.App || {};
+
+// Centralized runtime state for pagination, player, and UI behavior.
+App.state = {
+    currentPage: 1,
+    perPage: 12,
+    renderedVideoIds: new Set(),
+    hasNextPage: true,
+    isLoading: false,
+    hlsPlayer: null,
+    currentLoadController: null,
+    errorToastTimer: null,
+    playerMode: 'modal',
+    playerHome: null,
+    onFullscreenChange: null,
+    onWebkitEndFullscreen: null
+};
+
+// Local storage keys used across modules.
+App.constants = {
+    FAVORITES_KEY: 'favorites',
+    FAVORITES_VISIBILITY_KEY: 'favoritesVisible'
+};