fix: improve existing match handling in CSV import to ensure correct league and location updates

backend/services/matchService.js

@@ -185,25 +185,12 @@ class MatchService {
                     });
                 }
 
-                // Club teams already configured through MyTischtennis can be linked to
-                // leagues with a different display name than the click-TT CSV "Staffel".
-                // Update the existing match in that league so the schedule view receives
-                // the venue instead of creating a disconnected duplicate in a CSV league.
-                const existingMatch = await this.findExistingMatchForCSV(
-                    clubId,
-                    parsedDate,
-                    homeTeamName,
-                    guestTeamName
-                );
-                if (existingMatch) {
-                    if (location && existingMatch.locationId !== location.id) {
-                        await existingMatch.update({ locationId: location.id });
-                    }
-                    continue;
-                }
-
+                // Resolve the CSV teams before looking for a previous import.  A match may
+                // already exist in a legacy/generic league (for example "1. Kreisklasse"),
+                // while this CSV supplies the actual youth league.  In that case it must be
+                // moved to the CSV league as well, otherwise it is classified as adult.
                 const homeTeamId = await this.getOrCreateTeamId(
-                    row['HeimMannschaft'], 
+                    row['HeimMannschaft'],
                     row['HeimMannschaftAltersklasse'],
                     clubId,
                     league.id,
@@ -216,6 +203,28 @@ class MatchService {
                     league.id,
                     season.id
                 );
+
+                const existingMatch = await this.findExistingMatchForCSV(
+                    clubId,
+                    parsedDate,
+                    homeTeamName,
+                    guestTeamName
+                );
+                if (existingMatch) {
+                    const updates = {};
+                    if (location && existingMatch.locationId !== location.id) {
+                        updates.locationId = location.id;
+                    }
+                    if (existingMatch.leagueId !== league.id) {
+                        updates.leagueId = league.id;
+                        updates.homeTeamId = homeTeamId;
+                        updates.guestTeamId = guestTeamId;
+                    }
+                    if (Object.keys(updates).length > 0) {
+                        await existingMatch.update(updates);
+                    }
+                    continue;
+                }
                 matches.push({
                     date: parsedDate,
                     time: row['Termin'].split(' ')[1],