Improve bargekit CLI help coverage

[rogerchappel]

What changed

• Added a focused CLI help test that asserts the local, non-recording command surface is documented.

Why it matters

• Barge-in tooling needs clear operator trust boundaries; keeping the help path tested prevents accidental regressions in the first-run CLI guidance.

Verification

• npm run check passed.
• npm test passed.
• npm run smoke passed.

Remaining limitations

• This is a narrow CLI coverage improvement; it does not change runtime turn-taking behavior.