Preview before signing

POST /api/preview answers what would this mandate permit? with no wallet, no key and no gas. It registers the terms on a simulated chain, fires a plan at requestAction, and returns what the guard did with each action.

curl -X POST https://<host>/api/preview \
      -H 'content-type: application/json' \
      -d '{"terms":{"maxAggregate":"1000000000000"},"actions":12}'

The preview is the contract, not a model of it: the same artifacts, the same evaluation order, flags from IntentRecorded and every figure read back from headroom. Halving clause 3.4 moves the hold from action 9 to action 5. Nothing settles, and nothing enters the evidence spine.