For CI / scripting, a structured machine-readable output stream from `neo flow` / `neo step` is more useful than the line-printer's human text.
Scope
- `--json` flag on `neo flow` and `neo step`.
- Emits one JSON object per line (NDJSON): workflow events, step events, agent events, terminal summary.
- Schema matches `workflow.Event` (and `agent.Event` tagged with step name) shape.
Acceptance
- `neo flow code "X" --json | jq '.kind'` works.
- Existing line-printer behaviour unchanged without the flag.
For CI / scripting, a structured machine-readable output stream from `neo flow` / `neo step` is more useful than the line-printer's human text.
Scope
Acceptance