feat(runtime-host): own Gitoxide managed Write/Edit

[zhiiw]

Summary

Connects the accepted-ref data plane to the production-shaped Gitoxide Write/Edit owner.

Primary invariant: one managed Write/Edit derives from one accepted base and can publish only one operation-bound candidate proof.

Owner: Gitoxide managed Write/Edit owner.
Atomic boundary: candidate publication and durable proof adoption.
Failure state: ambiguous execution remains unsettled; no generic T2 fallback is allowed.
Rollback: deterministic no-effect failures settle without advancing the accepted head.

中文说明

本切片把 accepted-ref 数据面接入 Gitoxide Write/Edit owner。一次 managed Write/Edit 只能从一个 accepted base 派生，并且只能发布一个与 operation 绑定的 candidate proof；不确定状态保持 unsettled，禁止回退 generic T2。

[zhiiw]

Superseded by the rebuilt delivery stack #40 -> #41 -> #42. This extraction PR remains available as implementation and review history; no validated logic was discarded.

中文说明

该 extraction PR 已由从最新 main 重建的组合交付栈 #40 → #41 → #42 替代。这里仍保留实现与审查历史，已验证逻辑没有被丢弃。