`cycle` execute/verify is fail-closed for every runtime; no plugin mechanism for third-party runners (e.g. Pi)

Summary

We tried to use the official evolver cycle path to materialize Capsules offline and hit a hard wall (all on 2.0.30, re-verified today):

• evolver cycle --help: --runner enumerates only claude|codex|gemini;
• evolver cycle capabilities --json: all nine runtimes report execute/verify unsupported or experimental (only gemini is experimental; generic-chat — which we ingest from — is fully unsupported for execute);
• evolver solidify --dry-run --json → {"deprecated":true,"replacement":"evolver cycle; evolver review; evolver publish"};
• evolver cycle --runner gemini --limit 1 → action=fail status=refused reason=details-redacted.

Impact

Fully offline environments (or any runtime outside the three-name allowlist) cannot exercise the official cycle path at all. In our project we ended up building an equivalent offline orchestrator (run → independent validation → guarded strategy injection → cross-round metrics): https://github.com/stwhwing/pi-evox-lab

Suggestion

• Allow a pluggable external runner (a command/container contract plus --validation-cmd, similar to the existing runner test seam in autoDistillTranscript), so third-party runtimes can participate in cycle under their own containment;
• Or expose a documented "validation-only" cycle mode for offline harnesses.

Full report: https://github.com/stwhwing/pi-evox-lab/blob/main/docs/experiment-report.md (§19)