fix(multiplexer): use ignore stdio for close proc, drop unused constant import

src/multiplexer/shared.test.ts

@@ -41,7 +41,7 @@ describe('gracefulClosePane', () => {
       };
     });
 
-    const { gracefulClosePane, GRACEFUL_SHUTDOWN_DELAY_MS } =
+    const { gracefulClosePane } =
       await importShared();
     const ok = await gracefulClosePane('tmux', '%1', {
       ctrlC: ['send-keys', '-t', '%1', 'C-c'],

src/multiplexer/shared.ts

@@ -123,8 +123,8 @@ export async function gracefulClosePane(
     await new Promise((r) => setTimeout(r, GRACEFUL_SHUTDOWN_DELAY_MS));
 
     const proc = crossSpawn([binary, ...options.close], {
-      stdout: 'pipe',
-      stderr: 'pipe',
+      stdout: 'ignore',
+      stderr: 'ignore',
     });
     const exitCode = await proc.exited;