Add new activity events and enhance ActivityBloc for better state management

- Introduced LoadTripActivitiesPreservingSearch event to load trip activities while preserving search results.
- Added RemoveFromSearchResults and AddActivityAndRemoveFromSearch events for improved activity handling.
- Updated ActivitiesPage to show loading dialog during activity addition and provide user feedback.
- Increased maxResults for activity search to load more activities.

lib/components/home/show_trip_details_content.dart

@@ -42,7 +42,7 @@ class _ShowTripDetailsContentState extends State<ShowTripDetailsContent> {
           return; // Utiliser le cache
         }
 
-        // Sinon, lancer la recherche
+        // Sinon, lancer la recherche avec le maximum d'activités
         context.read<ActivityBloc>().add(
           widget.trip.hasCoordinates
               ? SearchActivitiesWithCoordinates(
@@ -50,14 +50,14 @@ class _ShowTripDetailsContentState extends State<ShowTripDetailsContent> {
                   latitude: widget.trip.latitude!,
                   longitude: widget.trip.longitude!,
                   category: null,
-                  maxResults: 6,
+                  maxResults: 100, // Charger le maximum d'activités possible
                   reset: true,
                 )
               : SearchActivities(
                   tripId: widget.trip.id!,
                   destination: widget.trip.location,
                   category: null,
-                  maxResults: 6,
+                  maxResults: 100, // Charger le maximum d'activités possible
                   reset: true,
                 ),
         );