Phase 1: Progress modal text, SiteSerializer fields, Notification store, SiteCard checklist

- Improved progress modal messages in ai/engine.py (Section 4)
- Added keywords_count and has_integration to SiteSerializer (Section 6)
- Added notificationStore.ts for frontend notifications (Section 8)
- Added NotificationDropdownNew component (Section 8)
- Added SiteSetupChecklist to SiteCard in compact mode (Section 6)
- Updated api.ts Site interface with new fields

frontend/src/services/api.ts

@@ -1523,6 +1523,8 @@ export interface Site {
   active_sectors_count: number;
   selected_sectors: number[];
   can_add_sectors: boolean;
+  keywords_count: number;
+  has_integration: boolean;
   created_at: string;
   updated_at: string;
 }