fix: use correct super_admin role in group ownership transfer check

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

backend/src/routes/chat.ts

@@ -417,7 +417,7 @@ const chatRoutes: FastifyPluginAsync = async (fastify) => {
       // Transfer ownership (only current owner or admin can do this)
       if (transferOwnerTo) {
         const userId = request.user.sub
-        if (createdBy !== userId && request.user.role !== 'admin') {
+        if (createdBy !== userId && request.user.role !== 'super_admin') {
           return reply.code(403).send({ error: 'Only the group creator can transfer ownership' })
         }
         await db.query('UPDATE chat_rooms SET created_by = $1 WHERE id = $2', [transferOwnerTo, roomId])