fix(evals): treat stream_select false return as timeout

When stream_select() returns false (signal interrupt, pipe error, or
descriptor closure), the read loop must kill the child process to
prevent proc_close() from hanging indefinitely on a zombied process.

Plan-by: glm-5.2
Acked-by: deepseek-v4-pro
Signed-off-by: kyau <git@kyaulabs.com>

Author: kyau

.opencode/evals/bin/includes/EvalRunner.php

@@ -298,6 +298,7 @@ private function readPipes($process, array $pipes, int $timeout, int $pid): arra
             $ready = @stream_select($read, $write, $except, $remainingSec, $remainingUsec);
 
             if ($ready === false) {
+                $timedOut = true;
                 break;
             }