- Validate --format argument before any side effects; raise typer.BadParameter
with a clear message for unsupported format values (fail-fast principle)
- Pass normalised fmt_value (lowercased) to format_output instead of raw fmt
to ensure consistent behaviour regardless of input casing
- Rewrite robot/helper_actor_remove_cli.py to exercise the real CLI end-to-end
via subprocess (no mocking); seeds a test actor via agents actor add, then
removes it with --format json and validates the JSON envelope
ISSUES CLOSED: #6491
Add Robot regression coverage for `actor remove --format json`, document the flag in the CLI synopsis, and record the fix in the changelog.\n\nISSUES CLOSED: #6491
HAL9000