feat(runtime): enforce managed mutation settlement authority

[zhiiw]

Summary

Close the Runtime settlement authority after a managed T1: no generic T2 fallback, no owner-supplied provider result, and no operation capability that survives terminal settlement.

Primary invariant

After managed T1, exactly one linear Runtime-owned operation capability may run, its result is captured as one bounded strict-JSON immutable snapshot, and the Host may submit terminal proof only.

• Owner: ToolRuntime
• Atomic boundary: managed admission mode chosen before T1; terminal publication adopts an exact durable outcome
• Failure state: malformed/missing proof, detached execution, oversized/non-JSON result, or owner failure becomes unsettled and never falls back to generic T2
• Rollback: no synthetic success; durable reservation remains for later authoritative recovery

What changed

• introduces the managed settlement union and managed/generic tagged lane
• makes the operation capability linear and revokes it at settlement
• keeps live provider result under Runtime ownership
• captures one bounded canonical immutable result snapshot
• requires exact durable outcome envelope adoption
• unifies Linux/macOS/Windows recovery inventory selection

Stack position

This is M2.3b, reviewed as the delta from M2.3a.

Base: codex/managed-workspace-mutation-reservation-m2-3a
Next: codex/managed-workspace-write-edit-production-m2-4

Validation

Runtime durable-boundary tests, CI planner tests, strict recovery inventory, and core/runtime/storage builds passed on the implementation branch.

Draft limitations

• this layer proves the Runtime seam but does not yet execute production managed Write/Edit
• final delivery must be rebuilt from latest upstream/main

中文说明

概要

本层收紧 managed T1 之后的 Runtime 权限边界：不允许 generic T2 fallback，不允许 Host 改写 provider result，也不允许 operation callback 越过终态继续执行。

Runtime 拥有唯一线性 operation capability，并在同一次有界 strict-JSON 遍历中生成不可变结果快照；Host 只能返回 terminal proof 与 exact durable outcome。任何畸形、缺失或不确定状态都 fail-stop。

这是 M2.3b；真实 Write/Edit 生产组合位于下一层。

[zhiiw]

Closed as an obsolete extraction/integration slice. The current delivery path is the merged Gitoxide foundation followed by #40 -> #41 -> #42. This PR remains available as design and implementation history.

中文说明

该 PR 属于旧 extraction/integration 栈，现已失去独立合并价值。当前交付路径是已合并的 Gitoxide 基础，然后依次审查 #40 → #41 → #42。这里继续保留设计、实现与审查历史。