feat: managed home fork lifecycle for decentralized orchestration (v1)

[AgentWrapper]

Scope\nImplement managed home fork lifecycle as first-class state.\n\n### Requirements\n- Add persistent managed_fork state (owner/repo/upstream/mode/last_sync)\n- Implement fork ensure bootstrap (create/reuse fork, set origin+upstream remotes)\n- Add role-based default mode: maintainers/contributors=upstream-first, others=fork-first\n- Add fork status command/API surface\n\n### Constraints\n- Keep scope limited to lifecycle + metadata + command wiring\n- Do not implement report pipeline in this issue\n\n### Validation\n- Add/adjust tests for state persistence and ensure flow\n- Provide test evidence in PR body