Concede message shown incorrectly + pre-existing ESLint errors in OnlineDebateRoom.tsx

When a user concedes the debate, both users receive "You win!" due to the WebSocket concede event being broadcast to all participants without checking who was the sender. Additionally, the file had 13 pre-existing ESLint errors including unused variables, empty catch blocks, and implicit any types.

Screenshot:

Steps to Reproduce:
Open a debate room in two browsers
One user clicks Concede
Both users incorrectly see "You win! "

Expected Behavior: Only the opponent should see "You win!". The conceding user should see "You have conceded."