tests: harden macOS REPL PTY acceptance

tests/m6_5_repl_acceptance.rs

@@ -289,12 +289,25 @@ fn m6_5_ctrl_c_sends_sigint() {
         r#"
             _G.h = pmacs.repl.spawn { argv = { "cat" } }
             _G.sigint_sent = false
+            _G.first_seen_running_at = nil
         "#,
         r#"
             local h = _G.h
             if not _G.sigint_sent then
               local status = pmacs.process.status(h._proc_id)
               if status and status.kind == "running" then
+                -- Running means the PTY child has been spawned, not
+                -- that the raw-mode /bin/sh trampoline has necessarily
+                -- completed stty + exec. macOS runners can observe that
+                -- gap; wait briefly so SIGINT targets cat, not the
+                -- setup shell.
+                if _G.first_seen_running_at == nil then
+                  _G.first_seen_running_at = pmacs.now_ms()
+                  return false
+                end
+                if pmacs.now_ms() - _G.first_seen_running_at < 100 then
+                  return false
+                end
                 pmacs.command.invoke("pmacs.repl.send-sigint-current")
                 _G.sigint_sent = true
               end
@@ -325,7 +338,10 @@ fn m6_5_exit_marker_uses_basename_with_leading_newline() {
             -- Marker starts with "\n[false exited with code 1]\n".
             return history:find("\n[false exited with code 1]\n", 1, true) ~= nil
         "#,
-        3000,
+        // PTY shutdown publishes the exit event only after a bounded
+        // final-output drain. macOS runners can spend most of the old
+        // 3s budget in spawn + that drain, even for /bin/false.
+        10_000,
     );
 }