feat(tournament): enhance tournament creation with group settings and winning sets logic

- Updated the tournamentService to set default values for tournament type, number of groups, and advancing participants for group tournaments.
- Adjusted the frontend logic to dynamically determine the number of winning sets based on the mini championship year, ensuring proper configuration for tournaments.

backend/services/tournamentService.js

@@ -743,7 +743,9 @@ class TournamentService {
                 name: tournamentName,
                 date,
                 clubId: +clubId,
-                type: '',
+                type: 'groups',
+                numberOfGroups: 1,
+                advancingPerGroup: 1,
                 winningSets: sets,
                 allowsExternal: false,
                 miniChampionshipYear: Y

frontend/src/views/TournamentTab.vue

@@ -1208,7 +1208,10 @@ export default {
             const tournament = tRes.data;
             this.currentTournamentName = tournament.name || '';
             this.currentTournamentDate = tournament.date || '';
-            this.currentWinningSets = tournament.winningSets || 3;
+            const defaultSets = tournament.miniChampionshipYear != null ? 1 : 3;
+            this.currentWinningSets = (tournament.winningSets != null && tournament.winningSets >= 1)
+                ? tournament.winningSets
+                : defaultSets;
             this.isGroupTournament = tournament.type === 'groups';
             // Defensive: Backend/DB kann (historisch/UI-default) 0/null liefern.
             // Für gruppenbasierte Turniere ohne Klassen brauchen wir hier aber eine sinnvolle Zahl,