Run test_curses_interactive in CI

From src/verify_distribution.py:
```python
@unittest.skipIf(os.name == "nt", "curses not available on Windows")
@unittest.skipIf("TERM" not in os.environ, "TERM not set")
def test_curses_interactive(self):
import curses

curses.initscr()
curses.endwin()
```

I believe this is getting skipped in GitHub Actions, but it's probably enough to run this inside a pty, we just need to set `TERM` to some valid value. If not we can try to run it in a real headless terminal like `screen`/`tmux` or something (just make sure we report the exit status correctly).