Stage Receipt
Every run writes exactly one receipt.
Use:
node scripts/write-stage-receipt.mjs --stage=<stage> --mode=<mode> --files=<files> --checks=<checks> --passed=<true|false> --handoff=<summary>
Modes: no-op, mutated, blocked, verified, routed, merged, cleanup.
Receipts must be compact and must not contain raw logs or secrets.