feat(delete): add undo toasts and harden delete modals

static/js/utils/undoHelpers.js

@@ -0,0 +1,55 @@
+import { showToast } from './uiHelpers.js';
+
+/**
+ * Undo a staged delete batch via the pending-delete endpoint.
+ * @param {string} batchId - The batch id returned by a staged delete response
+ * @param {Function|null} refreshFn - Called once after a successful restore (unless options.refresh is false)
+ * @param {Object} [options]
+ * @param {boolean} [options.showToast=true] - Suppress toasts (used by sequential multi-batch undo loops)
+ * @param {boolean} [options.refresh=true] - Suppress the refresh call (used by sequential multi-batch undo loops)
+ * @returns {Promise<boolean>} Whether the undo succeeded
+ */
+export async function handleUndoDelete(batchId, refreshFn, options = {}) {
+  const { showToast: showToastEnabled = true, refresh: refreshEnabled = true } = options;
+
+  try {
+    const response = await fetch('/api/lm/undo-delete', {
+      method: 'POST',
+      headers: { 'Content-Type': 'application/json' },
+      body: JSON.stringify({ batch_id: batchId }),
+    });
+
+    if (response.ok) {
+      if (refreshEnabled && typeof refreshFn === 'function') {
+        refreshFn();
+      }
+      if (showToastEnabled) {
+        showToast('toast.undo.restored', {}, 'success');
+      }
+      return true;
+    }
+
+    // Read the error body to distinguish an expired batch from other failures
+    let errorMessage = '';
+    try {
+      const body = await response.json();
+      errorMessage = body?.error || '';
+    } catch {
+      errorMessage = '';
+    }
+
+    if (showToastEnabled) {
+      if (response.status === 404 && errorMessage.toLowerCase().includes('expired')) {
+        showToast('toast.undo.expired', {}, 'error');
+      } else {
+        showToast('toast.undo.failed', { error: errorMessage || response.statusText }, 'error');
+      }
+    }
+    return false;
+  } catch (error) {
+    if (showToastEnabled) {
+      showToast('toast.undo.failed', { error: error.message }, 'error');
+    }
+    return false;
+  }
+}