fix(files): prevent autosave data loss on load lag and binary files

Guard FilesView autosave until the selected file has finished loading,
refuse binary/PDF/office/archive text saves, and add a persisted global
autoSaveEnabled setting (default true) under Settings → General.

Co-authored-by: Serhii Dziupin <makeittech@users.noreply.github.com>

packages/ui/src/lib/settings/search.ts

@@ -147,6 +147,13 @@ const SETTINGS_SEARCH_ITEMS: readonly SettingsSearchItem[] = [
     // Only the mobile composer applies this offset (ChatInput gates on isMobile).
     isAvailable: (ctx) => ctx.isMobile,
   },
+  {
+    id: 'appearance.auto-save-enabled',
+    page: 'general',
+    titleKey: 'settings.openchamber.visual.field.autoSaveEnabled',
+    descriptionKey: 'settings.openchamber.visual.field.autoSaveEnabledInfo',
+    keywords: ['editor', 'autosave', 'auto-save', 'files', 'save'],
+  },
   {
     id: 'appearance.expanded-editor-toolbar',
     page: 'general',