Implement lane orchestration kernel

[yvette-carlisle]

Summary

• add a normative lane-control state spec with ownership/liveness/policy/terminalization axes
• project Running Lanes from active ownership instead of liveness evidence, with orphan/retained/terminal buckets surfaced in status, inspect, evidence, and dashboard UI
• enforce review churn at checkpoint time, fence further mutating tools under the policy stop, and remove the fourth-round external-review reset path

Validation

• cargo make check
  • fmt-check
  • clippy
  • radar validate
  • site build/check
  • cargo vstyle curate --language rust --workspace --all-features
  • nextest: 1173 passed, 1 skipped

Refs XY-962, XY-963, XY-964, XY-965, XY-966, XY-967, XY-968