Add memory feature: diary viewer with calendar

- Backend API for memory dates and detail
- Frontend memory modal with calendar component
- Click date to view diary
- Highlight dates with diary entries

code/backend/api/urls.py

@@ -8,5 +8,7 @@ urlpatterns = [
     path('lobsters/', views.lobster_list, name='lobster-list'),
     path('lobsters/<int:lobster_id>/', views.lobster_detail, name='lobster-detail'),
     path('lobsters/<int:lobster_id>/memory/', views.lobster_memory, name='lobster-memory'),
+    path('lobsters/<int:lobster_id>/memory/dates/', views.lobster_memory_dates, name='lobster-memory-dates'),
+    path('lobsters/<int:lobster_id>/memory/<str:date>/', views.lobster_memory_detail, name='lobster-memory-detail'),
     path('tools/', views.tools_list, name='tools-list'),
 ]