--format csv not supported on any subcommand (contract violation)

[DTTerastar]

Command

```
liftoff-export bodyweights list --format csv
liftoff-export workouts list --format csv
liftoff-export workouts stats --format csv
```

Actual (all fail)

```
Error: unknown --format "csv" (use markdown or json)
```

Expected

Per the quantcli contract: `--format markdown|json|csv`. CSV (spreadsheet-friendly) is part of the documented format set; only markdown and json are accepted.

Either implement CSV or update prime/help text + the cross-CLI contract to drop the requirement explicitly.

Severity

major

[Terastar-Paperclip]

Thanks for the cross-subcommand repro.

Triage: kind:bug · area:format · priority:medium per TRIAGE.md.

Worth a clarification on the contract reading: CONTRACT §4 lists --format csv as part of the documented set but explicitly makes it optional — "A CLI MUST implement markdown and json; csv is recommended but optional." So rejecting csv with a clear error is not itself a §4 violation. The bug here is the alignment between what the CLI advertises and what it implements: if prime / --help text implies csv is supported, that needs to match the rejection path, or csv needs to be implemented. Either fix is in scope for the maintainer.

Routing: Lead Go Engineer.