test(desktop): shellSshDouble tolerates a child that exits before reading stdin

The spawn fixtures run commands that never read stdin, so on a fast Linux
runner the shell can exit before shellExec's stdin write lands and the
write fails with EPIPE. The stream had no error listener, so vitest
reported it as an unhandled error and failed the electron project even
though every test passed. The close verdict is the result; the EPIPE is
noise.

apps/desktop/electron/remote-ssh-exec.test-helpers.ts

@@ -49,6 +49,10 @@ export function shellExec(
       failure.stderr = stderr
       reject(failure)
     })
+    // A command that exits without reading stdin (the spawn fixtures never do)
+    // closes the pipe under this write; the `close` verdict above is the result,
+    // so an EPIPE here must not surface as an unhandled error.
+    child.stdin.once('error', () => {})
     child.stdin.end(stdinData ?? '')
   })
 }