refactor(autoFetchMatchResultsService, MYTISCHTENNIS_AUTO_FETCH_README.md, Optimization TODO): enhance data processing and documentation

- Refactored the `autoFetchMatchResultsService` to separate single and double player statistics processing into distinct methods, improving code clarity and maintainability.
- Updated the README to reflect the current status of rating updates and match results, marking them as active and detailing their functionalities.
- Closed several TODOs in the optimization documentation, confirming the implementation of previously outlined tasks and ensuring no open inline TODOs remain in the main views.

frontend/src/views/DiaryView.vue

@@ -3245,26 +3245,6 @@ export default {
             return setIds && setIds.size > 0;
         },
 
-        getActivityGroup(activityId) {
-            return this.activityGroupsMap[activityId] || '';
-        },
-
-        async updateActivityGroup(activityId, groupId) {
-            try {
-                // Hier würde normalerweise ein API-Call gemacht werden
-                // Für jetzt speichern wir es nur lokal
-                this.activityGroupsMap[activityId] = groupId || '';
-                
-                // TODO: API-Call zum Speichern der Gruppenzuordnung
-                // await apiClient.put(`/diary-date-activities/${activityId}/group`, { groupId });
-                
-                this.showInfo('Erfolg', 'Gruppenzuordnung aktualisiert', '', 'success');
-            } catch (error) {
-                console.error('Fehler beim Aktualisieren der Gruppenzuordnung:', error);
-                this.showInfo('Fehler', 'Fehler beim Aktualisieren der Gruppenzuordnung', '', 'error');
-            }
-        },
-
         // Bulk-Zuordnungen für Aktivitäten
         async assignAllMembersToActivity(activityId) {
             try {