feat(tournament): add debug logging for member eligibility checks in TournamentTab

- Introduced debug logging to track member eligibility filtering in the TournamentTab component, providing insights into birth year comparisons and class item constraints for a subset of members.
- This enhancement aids in troubleshooting and ensures clarity in the filtering logic for tournament participants.

frontend/src/views/TournamentTab.vue

@@ -1678,6 +1678,20 @@ export default {
                 if (parts.length >= 3) birthYear = parseInt(parts[2], 10);
             }
             if (birthYear == null || !Number.isFinite(birthYear)) return true;
+            
+            // Debug: Zeige Filterung für erste paar Mitglieder
+            if (Math.random() < 0.1) {
+                console.log('[memberEligibleForClass]', {
+                    member: `${member.firstName} ${member.lastName}`,
+                    birthYear,
+                    classItem: classItem.name,
+                    minBirthYear: classItem.minBirthYear,
+                    maxBirthYear: classItem.maxBirthYear,
+                    tooOld: classItem.minBirthYear != null && birthYear < classItem.minBirthYear,
+                    tooYoung: classItem.maxBirthYear != null && birthYear > classItem.maxBirthYear
+                });
+            }
+            
             if (classItem.minBirthYear != null && birthYear < classItem.minBirthYear) return false;
             if (classItem.maxBirthYear != null && birthYear > classItem.maxBirthYear) return false;
             return true;