[unohee]

Summary

• Disk gate (AGT-4785): the heartbeat measures free space (statfs, bavail) on every volume the daemon writes to and holds dispatch below autonomous.minFreeDiskGiB (default 10, 0 = off). It sits after the worktree sweep and before any fetch/claim, so cleanup keeps running. One notice per change of state. Reads fail open.
• workerSandbox was never passed to the runner: core/service.ts builds the runner config by hand-picked mapping and omitted the field. The runner saw undefined; the bash tool fences only on an explicit 'on', so the worker shell ran unfenced while the boot log said "Worker sandbox: on". Now mapped.

Verification

• npm run ci and npm run test:coverage (580 files / 7829 tests, thresholds met) pass locally.
• Mutations: dropping either mapping line fails service.test.ts; removing the gate return or ignoring the configured floor fails autonomousRunner.hostHealth.test.ts.
• Factory harness C6: 3/3 fail without hostHealth.ts, 3/3 pass with it.
• Fixed a flaky assertion that compared two live statfs readings for exact equality.

Not done

• Explicit dispatch (/api/work, exec --issue) is not held by the disk gate.
• A run that already failed with ENOSPC is still classified as a plain infra_error.
• Not checked: whether CLI entry points that build their own runner config carry workerSandbox.