Add UI animations: dialogs, tabs, settings, browser stagger, banner pulse

- Dialog modals: scale+fade entrance/exit with animated backdrop
- Tab panels: fade-in with subtle slide on switch
- Settings sections: content slide-down on expand
- Browser grid/list items: staggered cascade entrance animation
- Connection banner: slide-in + attention pulse on disconnect
- Accessibility: prefers-reduced-motion disables all animations

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

media_server/static/js/scripts.js

@@ -283,7 +283,7 @@ async function closeScriptDialog() {
 
     const dialog = document.getElementById('scriptDialog');
     scriptFormDirty = false;
-    dialog.close();
+    closeDialog(dialog);
     document.body.classList.remove('dialog-open');
 }
 
@@ -375,7 +375,7 @@ async function deleteScriptConfirm(scriptName) {
 
 function closeExecutionDialog() {
     const dialog = document.getElementById('executionDialog');
-    dialog.close();
+    closeDialog(dialog);
     document.body.classList.remove('dialog-open');
 }