feat(tournament): add mini championship functionality and enhance tournament class handling

- Introduced addMiniChampionship method in tournamentService to create tournaments with predefined classes for mini championships.
- Updated getTournaments method to filter tournaments based on type, including support for mini championships.
- Enhanced TournamentClass model to include maxBirthYear for age class restrictions.
- Modified tournamentController and tournamentRoutes to support new mini championship endpoint.
- Updated frontend components to manage mini championship creation and display, including localization for new terms.

backend/models/Tournament.js

@@ -39,6 +39,12 @@ const Tournament = sequelize.define('Tournament', {
         allowNull: false,
         defaultValue: false,
     },
+    miniChampionshipYear: {
+        type: DataTypes.INTEGER,
+        allowNull: true,
+        field: 'mini_championship_year',
+        comment: 'Jahr der Minimeisterschaft; nur gesetzt bei Minimeisterschaften'
+    },
 }, {
   underscored: true,
   tableName: 'tournament',

backend/models/TournamentClass.js

@@ -44,6 +44,13 @@ const TournamentClass = sequelize.define('TournamentClass', {
         defaultValue: null,
         field: 'min_birth_year',
         comment: 'Geboren im Jahr X oder später (>=)'
+    },
+    maxBirthYear: {
+        type: DataTypes.INTEGER,
+        allowNull: true,
+        defaultValue: null,
+        field: 'max_birth_year',
+        comment: 'Geboren im Jahr X oder früher (<=); für Altersklassen 12/10'
     }
 }, {
     underscored: true,