feat(tournaments): add update functionality for official tournaments

- Implemented an API endpoint to update the title of official tournaments, including error handling for non-existent tournaments.
- Enhanced the frontend to allow users to edit tournament titles directly, with input validation and feedback for successful updates or errors.
- Updated the German localization file to include new strings for editing titles and error messages.

backend/services/officialTournamentService.js

@@ -295,6 +295,14 @@ class OfficialTournamentService {
     return out;
   }
 
+  async updateOfficialTournament(clubId, id, { title }) {
+    const t = await OfficialTournament.findOne({ where: { id, clubId } });
+    if (!t) return null;
+    if (title !== undefined) t.title = title;
+    await t.save();
+    return t.toJSON();
+  }
+
   async deleteOfficialTournament(clubId, id) {
     const t = await OfficialTournament.findOne({ where: { id, clubId } });
     if (!t) return false;