The CLI uses ignore_unknown_options=True so a prompt can contain flag-like
text, but that also meant the short -h flag was not recognized as the help
flag — it fell through to the PROMPT argument and was sent to Navi as a
message ("you've asked for help again..."). --help already worked because
Click auto-generates the long form.

Add help_option_names=["-h", "--help"] to context_settings so -h is a known
help option, parsed before the ignore-unknown fallback.

Test: -h via CliRunner exits 0 and shows usage. 577 passed, 1 skipped.

Co-Authored-By: Claude <noreply@anthropic.com>