select.select skips file objects, so a Popen pipe is never ready

Found 2026-10-20 while probing for Vloot. select.select([p.stdout], [], [], 2.0) returns an empty ready list immediately, even though the child writes within the timeout. CPython reports the pipe as ready. PySelectReady (pylib.pas) polls only integer entries and silently skips anything else, so a TPyFile (a Popen pipe or an open() file) is never polled. It should take fileno() from a TPyFile entry and return the original object in the ready list. select.select([p.stdout.fileno()], ...) already works and matches CPython.

os.read(fd, n) and os.set_blocking(fd, flag) also don't exist ("undefined variable (os)"), so the usual select-then-read loop can't be written yet.