refactor(delete): make undo unconditional, remove undo toggle and button delay

- Remove delete_undo_enabled setting (backend default, frontend state,
  settings modal UI, 10 locales); staged deletes with 30s undo are now
  the only delete path and stale settings keys are silently ignored
- Remove the 1500ms delete-button arm delay (armDeleteButton) from all
  delete modals; misclicks are recoverable via the undo toast
- Delete modal always shows the recoverable warning
- Log the first staged file path in staging log lines for easier support

static/js/managers/BulkManager.js

@@ -1,7 +1,6 @@
 import { state, getCurrentPageState } from '../state/index.js';
 import { showToast, showActionToast, copyToClipboard, sendLoraToWorkflow, sendEmbeddingToWorkflow, buildLoraSyntax, getNSFWLevelName } from '../utils/uiHelpers.js';
 import { handleUndoDelete } from '../utils/undoHelpers.js';
-import { armDeleteButton } from '../utils/modalUtils.js';
 import { updateCardsForBulkMode } from '../components/shared/ModelCard.js';
 import { modalManager } from './ModalManager.js';
 import { getModelApiClient, resetAndReload } from '../api/modelApiFactory.js';
@@ -630,7 +629,6 @@ export class BulkManager {
         }
 
         modalManager.showModal('bulkDeleteModal');
-        armDeleteButton(document.getElementById('bulkDeleteModal'));
     }
 
     async confirmBulkDelete() {

static/js/managers/SettingsManager.js

@@ -1111,12 +1111,6 @@ export class SettingsManager {
             includeTriggerWordsCheckbox.checked = state.global.settings.include_trigger_words || false;
         }
 
-        // Set delete undo setting (defaults to enabled)
-        const deleteUndoEnabledCheckbox = document.getElementById('deleteUndoEnabled');
-        if (deleteUndoEnabledCheckbox) {
-            deleteUndoEnabledCheckbox.checked = state.global.settings.delete_undo_enabled ?? true;
-        }
-
         // Set lora syntax format
         const loraSyntaxFormatSelect = document.getElementById('loraSyntaxFormat');
         if (loraSyntaxFormatSelect) {