fix(TeamManagement): correct member eligibility logic and add eligibility check for planning teams

- Updated the eligibility comparison logic to ensure correct member and team index validation.
- Introduced a new function to check if a member is eligible for a planning team based on age group and gender.
- Enhanced the team drop functionality to include eligibility validation, providing user feedback for ineligible members.

frontend/src/views/TeamManagementView.vue

@@ -979,7 +979,7 @@ export default {
       if (memberIndex < 0 || teamIndex < 0) {
         return false;
       }
-      return memberIndex <= teamIndex;
+      return memberIndex >= teamIndex;
     };
 
     const getMemberEligibilityLabel = (member, teamAgeGroup) => {
@@ -1218,6 +1218,16 @@ export default {
       planningDraggingMemberId.value = Number(member?.id);
     };
 
+    const isEligibleForPlanningTeam = (memberId, teamId) => {
+      const team = planningLocalTeams.value.find((entry) => Number(entry.id) === Number(teamId));
+      if (!team) return false;
+      const member = planningMemberById.value.get(planningMemberKey(memberId));
+      if (!member) return false;
+      const teamAgeGroup = team.teamAgeGroup || 'adult';
+      const teamGender = team.teamGender || 'open';
+      return isEligibleForTeam(member, teamAgeGroup, teamGender);
+    };
+
     const setPlanningTeamStatus = (teamId, state) => {
       const key = String(teamId);
       planningTeamSaveStatus.value = {
@@ -1305,10 +1315,20 @@ export default {
       planningAutosaveTimers.set(key, timer);
     };
 
-    const onPlanningDropToTeam = (teamId) => {
+    const onPlanningDropToTeam = async (teamId) => {
       const memberId = Number(planningDraggingMemberId.value);
       const targetTeamId = Number(teamId);
       if (!memberId || !targetTeamId) return;
+      if (!isEligibleForPlanningTeam(memberId, targetTeamId)) {
+        await showInfo(
+          t('messages.warning'),
+          'Dieses Mitglied ist für die gewählte Mannschaft nicht spielberechtigt (Geschlecht/Altersklasse).',
+          '',
+          'warning'
+        );
+        planningDraggingMemberId.value = null;
+        return;
+      }
       const previousEntry = planningAssignments.value.find((entry) => Number(entry.memberId) === memberId);
       const sourceTeamId = previousEntry ? Number(previousEntry.teamId) : null;
       const withoutMember = planningAssignments.value.filter((entry) => Number(entry.memberId) !== memberId);