fix: resolve cmux test lint errors (noUnusedVariables, organizeImports)

src/multiplexer/cmux/index.test.ts

@@ -240,7 +240,6 @@ describe('CmuxMultiplexer', () => {
     const pane = await instance.spawnPane('s', 'agent', 'http://server', '/r');
     process.env.CMUX_SOCKET_PATH = '/tmp/socket-b';
     await instance.closePane(pane.paneId ?? '');
-    const close = calls.find((call) => call.includes('close-surface'));
     for (const operation of [
       'new-split',
       'respawn-pane',

src/multiplexer/cmux/session-lifecycle.test.ts

@@ -1,7 +1,7 @@
 import { beforeEach, describe, expect, mock, test } from 'bun:test';
 import type { Multiplexer } from '../types';
-import { CmuxSessionLifecycle } from './session-lifecycle';
 import { CmuxClosePolicy } from './close-policy';
+import { CmuxSessionLifecycle } from './session-lifecycle';
 import { CmuxSessionStore } from './session-state';
 
 function deferred<T>() {