refactor: remove unused classroom fields

apps/server/src/database/database-migrations.service.ts

@@ -14,6 +14,26 @@ export class DatabaseMigrationsService implements OnApplicationBootstrap {
     await this.backfillOrganizations();
     await this.normalizeClassDates();
     await this.protectAttendanceHistory();
+    await this.removeUnusedClassroomColumns();
+  }
+
+  private async removeUnusedClassroomColumns(): Promise<void> {
+    const runner = this.dataSource.createQueryRunner();
+    await runner.connect();
+    try {
+      const tables = await runner.getTables(['classrooms']);
+      if (tables.length === 0) return;
+
+      const table = await runner.getTable('classrooms');
+      const columnNames = new Set(table?.columns.map((column) => column.name) ?? []);
+      for (const columnName of ['course_type', 'supervisor']) {
+        if (columnNames.has(columnName)) {
+          await runner.query(`ALTER TABLE classrooms DROP COLUMN ${columnName}`);
+        }
+      }
+    } finally {
+      await runner.release();
+    }
   }
 
   private async ensureAiConfigTable(): Promise<void> {