feat(runtime-host): close managed Write/Edit mutation recovery

[zhiiw]

Summary

Compose managed Write/Edit from immutable Git base content through a detached worker transform, immutable candidate capture, atomic SQLite successor acceptance, and crash-convergent projection publication.

Primary invariant

A managed Write/Edit is determined by the exact accepted base blob, exact operation, and exact resulting blob. The mutable worktree is only a disposable projection and is never the transform data plane. After durable intent, every observable combination of path, registration, HEAD/index, and lock converges or fails closed; Git porcelain is not treated as an atomic transaction.

• Owner: Runtime Host composition across the already-separated Runtime, SQLite, Git candidate, registration-reconciliation, and projection owners
• Atomic boundary: T1 fixes durable mode; worker transforms immutable base content; SQLite atomically accepts T2 + successor + head; projection publication uses same-filesystem directory rename
• Failure states: successor committed, no-workspace-change committed, operation-failed-no-effect committed, or unsettled
• Rollback/recovery: never rerun a committed effect; durable intent reconciles partial Git registration and projection states

What changed

• adds detached Git transform protocol v7 for managed Write/Edit
• removes managed mutation worker access to the workspace filesystem
• binds base content/OID and result content/OID end to end
• builds candidates directly from Runtime-owned result content through a private Git index
• separates worktree add --no-checkout registration from candidate materialization
• preserves and rebuilds registration-only, path-only, and incomplete-checkout staging artifacts
• removes git worktree move; publication now uses atomic directory rename followed by idempotent git worktree repair
• reconciles both path-ahead-of-registration and registration-ahead-of-path split states
• gives old quarantine and new canonical projection different per-worktree gitdirs, HEADs, and indexes
• proves quarantine reset/add cannot mutate canonical HEAD/index or the managed ref
• rejects symlink/junction identity replacement without deleting through child paths
• uses compact owner-owned projection carrier paths for the Windows Git path budget; full identity remains in durable evidence

Stack position

This is M2.4, the fifth Draft in this review stack.

Base: codex/managed-workspace-mutation-runtime-admission-m2-3b

Validation

• core/runtime/storage/runtime-host builds passed
• full candidate suite: 16 passed, 5 platform/stress skips, 0 failed; reverse registration/path split targeted regression also passed
• strict Windows recovery inventory: 31 total, 30 passed, 1 explicit packaged-worker skip, 0 failed
• production-shaped projection test kills a real child process after staging registration, after each directory rename before repair, and after each repaired publication boundary
• deterministic tests cover registration-only, path-only, incomplete checkout, and both registration/path split directions
• Windows junction tamper and quarantine Git-control isolation regressions passed
• formatting and git diff --check passed

Draft limitations

• API-only Draft: Desktop and CLI do not create this managed coding mode yet
• quarantine/partial-artifact quota, diagnostics, and Git-owned safe GC remain M4 work
• full conversation continuation remains M3; this PR closes the managed Write/Edit effect/version seam
• power-loss durability is not claimed

中文说明

概要

本层闭合 managed Write/Edit 的 effect/version seam：transform 不读取或覆盖可变 worktree，而是从 accepted Git base 的不可变内容计算结果；candidate 绑定 exact result blob；SQLite 原子提交成功 T2、successor 与 canonical head。

这轮不再假设 git worktree add/move 是原子操作：

• staging 用 worktree add --no-checkout 把 registration 与 checkout 拆开；
• registration-only、path-only、未完成 checkout 都会整体保留并从 immutable candidate 重建；
• 删除 git worktree move，目录发布只用同文件系统原子 rename；
• rename 后用 git worktree repair 根据实际存在路径幂等修复 registration；
• path 先移动或 registration 先前进的两个方向都有回归测试。

旧 quarantine 与新 canonical projection 仍拥有不同的 per-worktree gitdir、HEAD 与 index，因此从 quarantine 执行 git reset 或 git add 不会改变 canonical projection 或 managed ref；外部用户字节完整保留。

当前仍是 API-only Draft，Desktop/CLI 尚未接入。完整对话 continuation 属于 M3；quarantine/partial artifact 的配额、诊断以及先撤销 Git registration 再清理目录的安全 GC 属于 M4。

[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。