- Remove redundant platform= test seam from _terminal_may_leak_cpr();
use monkeypatch.setattr(sys, 'platform', ...) consistently in both
test files.
- Wrap PTY tests in try/finally for fd cleanup on assertion failure.
- Guard select.select() in terminal thread against OSError after fd
close (fixes PytestUnhandledThreadExceptionWarning).
- Trim PR-number reference from test module docstring.
Add a delayed-CPR PTY harness (no SSH) plus selection/Application
assertions for POSIX local and Windows preserve-default. Update the
gating unit test to the new contract.