XY-193 Move review and repair policy ownership into Maestro runtime

[yvette-carlisle]

Summary

• add runtime-owned issue_review_checkpoint handling for handoff and retained repair phases
• persist lane-level review policy state in the run activity marker and enforce runtime stop boundaries for exhausted, blocked, and architecture-review checkpoints
• require current-head clean checkpoints before handoff or repair completion, and align prompts/specs/skills/tests with the new ownership model

Follow-up

• tracks post-XY-193 research escalation policy separately in XY-208

Verification

• cargo make fmt-check
• cargo make lint
• cargo make test
• git diff --check