feat(settings): add delete_undo_enabled toggle

static/js/managers/SettingsManager.js

@@ -1111,6 +1111,12 @@ 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) {

static/js/state/index.js

@@ -58,6 +58,7 @@ const DEFAULT_SETTINGS_BASE = Object.freeze({
     strip_lora_on_copy: false,
     use_new_license_icons: true,
     group_by_model: false,
+    delete_undo_enabled: true,
     llm_provider: 'openai',
     llm_api_key: '',
     llm_api_base: '',