v0.18.8 — project-orchestrator hardening + verify-or-revert demo

Ninth adversarial review (the chimera project loop + kanban DAG) — 7 findings, 6 fixed and regression-tested. The core "the spec is the only authority of done" invariant held. Ships with a new example demonstrating the honest artifact: a failed change caught and reverted with a receipt.

Added

• examples/revert_demo/ — verify-or-revert, demonstrated. Deterministic and model-free: it copies a sample workspace, injects a regression, runs the acceptance check (fails), reverts to the checkpoint, and re-checks (passes) — printing a receipt at each step. Drives the real primitives behind chimera solve/chimera project (WorkspaceGuard + CommandVerifier) and exits non-zero if verify-or-revert ever failed to protect the tree.

Fixed

• max_iterations is durable across a resume. project run/step/approve rebuilt the config with the default 20, overriding a --max-iterations N set at start (defeating the runaway rail). The rails are now persisted in project.json and rebuilt from disk on resume.
• A spec with no required requirements is refused instead of vacuously reporting "done" — an empty/misparsed requirements: block passed check_drift (which starts aligned=True).
• project.json is written atomically (temp + replace), like the board.
• A card left in doing by a crash is recovered to backlog and retried instead of orphaned into a permanent "no ready card" escalation.
• deny_card no longer raises if its card is gone from the board.
• A required requirement depending on an unsatisfied optional one now progresses (the optional dependency gets worked).

Gate: 1425 passed / 3 skipped, mypy + ruff green.

Install: pip install --upgrade 'chimera-agent[full]'