chore(dependencies): update package versions in package-lock.json and package.json

- Upgraded nodemailer from version 7.0.9 to 8.0.4 for improved email handling.
- Updated brace-expansion, flatted, picomatch, and socket.io-parser to their latest versions across frontend and backend for better performance and security.
- Incremented versions of other dependencies like sequelize and jspdf to ensure compatibility and access to new features.

frontend/src/components/tournament/TournamentParticipantsTab.vue

@@ -11,7 +11,7 @@
             <h4>{{ $t('tournaments.participants') }}</h4>
             <div class="participants-summary">
                 <span class="summary-chip">{{ allParticipantsCount }} {{ $t('tournaments.participants') }}</span>
-                <span v-if="unassignedParticipantsCount > 0" class="summary-chip summary-chip-warning">
+                <span v-if="hasTournamentClasses && unassignedParticipantsCount > 0" class="summary-chip summary-chip-warning">
                     {{ unassignedParticipantsCount }} {{ $t('tournaments.withoutClass') }}
                 </span>
                 <span v-if="participantsWithConflictsCount > 0" class="summary-chip summary-chip-warning">
@@ -30,7 +30,7 @@
                     <span class="filter-chip-count">{{ allParticipantsCount }}</span>
                 </button>
                 <button
-                    v-if="unassignedParticipantsCount > 0"
+                    v-if="hasTournamentClasses && unassignedParticipantsCount > 0"
                     type="button"
                     class="filter-chip filter-chip-warning"
                     :class="{ active: participantFilter === 'withoutClass' }"
@@ -60,7 +60,7 @@
                     <span class="filter-chip-count">{{ gaveUpParticipantsCount }}</span>
                 </button>
             </div>
-            <div v-if="unassignedParticipantsCount > 0" class="participants-callout">
+            <div v-if="hasTournamentClasses && unassignedParticipantsCount > 0" class="participants-callout">
                 <div class="participants-callout-main">
                     <div>
                         <strong>{{ $t('tournaments.withoutClass') }}:</strong>
@@ -675,6 +675,9 @@ export default {
         };
     },
     computed: {
+        hasTournamentClasses() {
+            return Array.isArray(this.tournamentClasses) && this.tournamentClasses.length > 0;
+        },
         allParticipantsCount() {
             return this.allParticipantsList().length;
         },
@@ -844,9 +847,10 @@ export default {
         },
         participantAssignmentHint(participant) {
             if (participant.classId != null) return '';
+            if (!this.hasTournamentClasses) return '';
             const eligibleClasses = this.tournamentClasses.filter(classItem => this.participantEligibleForClass(participant, classItem));
             if (eligibleClasses.length === 0) {
-                return this.$t('tournaments.noEligibleClass');
+                return '';
             }
             return this.$t('tournaments.eligibleClassesHint', { classes: eligibleClasses.map(classItem => classItem.name).join(', ') });
         },