feat(runtime-host): preserve Agent Graph history across revisions

[M4n5ter]

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English

\n\n## Summary\n\n- Allow Session revisions to retain verified terminal Agent Graph child, Run, and Artifact references.\n- Keep the source Graph authority unchanged while the new revision starts with an independent empty Graph.\n- Reject ordinary branches, live Graph state, and incomplete or inconsistent linked provenance.\n\n## Behavior\n\nA completed Agent Graph result remains readable after edit-and-resend without cloning, reparenting, or restarting its child Sessions. The Host validates Graph lifecycle state and each linked Run and Artifact before preserving those historical references. Revision-family lifecycle operations continue to retain the physical child owners.\n\n## Validation\n\n- Runtime Host: 616 tests passed\n- Runtime Agent Graph and conversation-copy focused tests: 17 tests passed\n- Workspace typecheck and lint passed\n- Real two-client UDS revision, restart, and lifecycle regression passed\n\nPart of #1167 and #853.\n\n

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中文

\n\n## 概要\n\n- 允许 Session revision 保留经过验证且已终态的 Agent Graph child、Run 与 Artifact 引用。\n- 保持源 Graph authority 不变，新 revision 使用独立且为空的 Graph。\n- 对普通 branch、仍在运行的 Graph，以及缺失或不一致的关联 provenance 直接拒绝。\n\n## 行为\n\n完成后的 Agent Graph 结果在 edit-and-resend 后仍可读取，同时不会复制、重新归属或重启原有 child Session。Host 会先验证 Graph 生命周期，再逐项验证关联 Run 与 Artifact，之后才保留这些历史引用。Revision family 的生命周期操作仍会保留实际拥有这些引用的 child。\n\n## 验证\n\n- Runtime Host：616 项测试通过\n- Runtime Agent Graph 与 conversation-copy 定向测试：17 项通过\n- Workspace typecheck 与 lint 通过\n- 真实双 Client UDS revision、重启与生命周期回归通过\n\n属于 #1167 与 #853 的一部分。\n\n