feat(delete): shorten undo window to 20s and make undo toast dismissible

static/css/components/toast.css

@@ -107,6 +107,24 @@
     white-space: nowrap;
 }
 
+.toast-close-btn {
+    flex-shrink: 0;
+    padding: 0 4px;
+    background: transparent;
+    color: var(--text-color);
+    border: none;
+    border-radius: 4px;
+    font-size: 1.1em;
+    line-height: 1;
+    opacity: 0.5;
+    cursor: pointer;
+    transition: opacity 0.2s ease;
+}
+
+.toast-close-btn:hover {
+    opacity: 1;
+}
+
 /* Responsive adjustments */
 @media (max-width: 768px) {
     .toast {

static/js/utils/uiHelpers.js

@@ -236,11 +236,11 @@ export function showToast(key, params = {}, type = 'info', fallback = null) {
  * @param {Object} [options]
  * @param {string} [options.actionText] - Label for the action button (button omitted when empty)
  * @param {Function} [options.onAction] - Callback invoked at most once on button click
- * @param {number} [options.durationMs=30000] - How long the toast stays visible
+ * @param {number} [options.durationMs=20000] - How long the toast stays visible
  * @param {boolean} [options.countdown=true] - Show a ticking `(N)s` countdown
  */
 export function showActionToast(key, params = {}, type = 'info', options = {}) {
-  const { actionText, onAction, durationMs = 30000, countdown = true } = options;
+  const { actionText, onAction, durationMs = 20000, countdown = true } = options;
 
   const isPlainMessage = typeof key === 'string' && /\s/.test(key);
   const message = isPlainMessage ? key : translate(key, params);
@@ -295,6 +295,20 @@ export function showActionToast(key, params = {}, type = 'info', options = {}) {
       }
     }, 1000);
   }
+
+  // Manual close button: hides the toast early without firing onAction. The
+  // backend undo window keeps running and the batch is purged when it expires.
+  const closeBtn = document.createElement('button');
+  closeBtn.type = 'button';
+  closeBtn.className = 'toast-close-btn';
+  closeBtn.textContent = '×';
+  closeBtn.setAttribute('aria-label', translate('common.actions.close'));
+  closeBtn.addEventListener('click', (event) => {
+    event.preventDefault();
+    clearCountdown();
+    dismiss();
+  });
+  toast.append(closeBtn);
 }
 
 export function restoreFolderFilter() {