feat(kick-system): add translated kick reasons with error codes

- Add kickReason field to ServerErrorMessage schema with enum values
- Display translated kick messages instead of generic "Kicked from game"
- Include error codes (KICK_ADMIN, KICK_MULTI_TAB, KICK_LOBBY_CREATOR) for debugging
- Update kick handlers in GameServer, PostJoinHandler, and Worker to pass reasons
- Modify showErrorModal to handle kick-specific formatting without duplication

src/server/Worker.ts

@@ -294,7 +294,7 @@ export async function startWorker() {
         return;
       }
 
-      game.kickClient(clientID);
+      game.kickClient(clientID, "kick_admin");
       res.status(200).send("Player kicked successfully");
     }),
   );