feat(sprint18): editor autosave/reset, admin auth, QR reuse, Ed25519 prep

- Project editor: persist draft to localStorage, restore on reload,
  last-saved/draft-restored status indicators, section/whole-draft reset
  with confirmation.
- Extract shared QR/polling/expiry engine from TelegramLoginComponent
  (shared/qr-login) and reuse it for a new admin login flow.
- Admin authentication kept fully separate from customer session:
  own cookie/localStorage keys, signals, guard, and header interceptor
  (core/admin-auth).
- ?login=true / ?adminLogin=true open the respective login dialog for
  manual testing.
- Ed25519 challenge/verify interfaces (fail-closed no-op binding) ready
  for backend delivery.
- Document autosave/reset/admin-auth/QR-reuse/Ed25519 model and the
  remaining full-field-coverage gap in docs/Project-Editor.md.

src/app/features/project-editor/models/project-editor.model.ts

@@ -16,12 +16,28 @@ export type ProjectEditorSectionId =
 
 export interface ProjectEditorState {
   bootstrap: BootstrapConfig | null;
+  originalBootstrap: BootstrapConfig | null;
   importError: string | null;
   activeSection: ProjectEditorSectionId;
   status: 'draft' | 'published';
   lastSavedBootstrap: BootstrapConfig | null;
+  lastSavedAt: number | null;
+  draftRestored: boolean;
 }
 
+export const EDITOR_SECTION_BOOTSTRAP_KEYS: Partial<Record<ProjectEditorSectionId, (keyof BootstrapConfig)[]>> = {
+  general: ['tenant', 'seo'],
+  branding: ['branding'],
+  theme: ['theme'],
+  header: ['header'],
+  footer: ['footer', 'company'],
+  homepage: ['pages'],
+  widgets: ['pages'],
+  features: ['featureFlags', 'userExperience', 'catalog', 'productPage'],
+  languages: ['localization'],
+  navigation: ['navigation'],
+};
+
 export interface ProjectEditorWidgetPreset {
   id: string;
   type: string;