feat(game-api): add opt-in live swarm comparison

[christopherjnelson]

Summary

• Add a separately opted-in live comparison of OpenRouter Agent Zero with Jev workers versus the same Zero planner and deterministic legal-candidate workers.
• Require explicit provider-cost acknowledgement and Zero model selection; bound seeds, ticks, roster, attempts, and credit admission.
• Emit safe per-tick, per-run, and aggregate JSON metrics, plus an offline Markdown summary command. Preserve the existing offline comparison and legacy mode.

Validation

• pnpm validate passed.
• pnpm test:e2e passed.
• No paid comparison was run; a no-acknowledgement CLI smoke check refused provider execution.

Operator follow-up

Select an OpenRouter model and run the documented command in docs/LIVE_SWARM_COMPARISON.md with both provider keys. Treat outputs as reproducible-input observations, not deterministic results.