refactor(multiplexer): use gracefulClosePane in tmux

src/multiplexer/tmux/index.ts

@@ -5,7 +5,7 @@
 import type { MultiplexerLayout } from '../../config/schema';
 import { crossSpawn } from '../../utils/compat';
 import { log } from '../../utils/logger';
-import { buildOpencodeAttachCommand, findBinary } from '../shared';
+import { buildOpencodeAttachCommand, findBinary, gracefulClosePane } from '../shared';
 import type { Multiplexer, PaneResult } from '../types';
 
 const TMUX_LAYOUT_DEBOUNCE_MS = 150;
@@ -113,54 +113,13 @@ export class TmuxMultiplexer implements Multiplexer {
   }
 
   async closePane(paneId: string): Promise<boolean> {
-    if (!paneId) {
-      log('[tmux] closePane: no paneId provided');
-      return false;
-    }
-
     const tmux = await this.getBinary();
-    if (!tmux) {
-      log('[tmux] closePane: tmux binary not found');
-      return false;
-    }
-
-    try {
-      // Send Ctrl+C for graceful shutdown
-      log('[tmux] closePane: sending Ctrl+C', { paneId });
-      const ctrlCProc = crossSpawn([tmux, 'send-keys', '-t', paneId, 'C-c'], {
-        stdout: 'pipe',
-        stderr: 'pipe',
-      });
-      await ctrlCProc.exited;
-
-      // Wait for graceful shutdown
-      await new Promise((r) => setTimeout(r, 250));
-
-      // Kill the pane
-      log('[tmux] closePane: killing pane', { paneId });
-      const proc = crossSpawn([tmux, 'kill-pane', '-t', paneId], {
-        stdout: 'pipe',
-        stderr: 'pipe',
-      });
-
-      const exitCode = await proc.exited;
-      const stderr = await proc.stderr();
-
-      log('[tmux] closePane: result', { exitCode, stderr: stderr.trim() });
-
-      if (exitCode === 0) {
-        // Rebalance panes after bursts of child sessions settle.
-        this.scheduleLayout();
-        return true;
-      }
-
-      // Pane might already be closed
-      log('[tmux] closePane: failed (pane may already be closed)', { paneId });
-      return false;
-    } catch (err) {
-      log('[tmux] closePane: exception', { error: String(err) });
-      return false;
-    }
+    const closed = await gracefulClosePane(tmux, paneId, {
+      ctrlC: ['send-keys', '-t', paneId, 'C-c'],
+      close: ['kill-pane', '-t', paneId],
+    });
+    if (closed) this.scheduleLayout();
+    return closed;
   }
 
   async applyLayout(