fix(fcs): add IOM limit validation, improve risks examples, and enhance error handling - #48

Summary

• IOM list: add a --limit cap of 100 with a clear error message when exceeded (the API returns an error for larger values)
• Risks list: correct and expand the --filter examples — severity values must be uppercase (HIGH, CRITICAL), and the cloud_provider FQL field is unreliable so examples now show --grep and jq alternatives; fix sort syntax from field.desc to field|desc
• Error handling: add a filterHints map so HandleAPIError surfaces known filter field names on 400 responses; add human-readable keys to featureRequirements for the compliance 404 case

Test plan

• falcon fcs iom list --limit 101 returns a clear error
• falcon fcs risks list --filter "severity:'HIGH'" works; --filter "severity:'High'" documents the uppercase requirement
• falcon fcs risks list --sort "severity|desc" works
• HandleAPIError on a 400 from ContainerCombined includes the filter field hint
• Compliance 404 returns the feature-not-provisioned message via the human-readable keys