Choreograph: guide parameter steps + child card fix

- Auto-generate param steps in guide (token/path = selection, others = ?{} queries)
- CSV-style array parser for comma-separated param values
- parseCSV utility (splits on commas, respects double-quoted segments)
- Store param values on guide state, append as --flags in synthetic run
- Fix child status card: use runtimeOpts.parent for suppression
- Add 'parent' to knownFlags (prevents leaking as scene param)