Fix non-default CODEX_HOME state resolution

[zendext]

背景

Track the implementation of kxn/codex-remote-feishu#904 in this fork.

The daemon passes CODEX_HOME to headless Codex children, but its persisted thread catalog and turn-patch storage still derive paths from $HOME/.codex. The generated systemd and launchd service definitions also omit an explicitly selected CODEX_HOME.

目标

Use one resolved Codex home across headless children, persisted thread discovery, turn-patch storage, and managed service restarts while preserving the existing $HOME/.codex fallback.

完成标准

1. A valid non-empty CODEX_HOME resolves the default SQLite catalog to $CODEX_HOME/state_5.sqlite.
2. Turn-patch session and state paths derive from the same resolved Codex home ($CODEX_HOME/sessions and $CODEX_HOME/codex-remote-feishu/current-thread-patches).
3. An unset CODEX_HOME preserves the current $HOME/.codex behavior.
4. Generated systemd and launchd service definitions preserve the selected CODEX_HOME.
5. Focused regression tests cover custom and default resolution plus managed-service rendering.
6. User-facing installation documentation explains the supported non-default CODEX_HOME behavior.

建议范围

• internal/codexstate：统一默认 Codex Home、SQLite catalog、sessions 与 turn-patch state 的路径解析。
• internal/app/daemon：让生产构造调用复用同一个已解析 Codex Home。
• internal/app/install：在 systemd 与 launchd 定义中保留显式 CODEX_HOME。
• docs/general/user-guide.md：说明非默认 CODEX_HOME 的安装与自动启动行为。
• 对应 focused tests 与仓库验证。

实现参考

• 复用 internal/config/codex_model_provider_env.go 已有的 CODEX_HOME 目录校验语义。
• 将默认 Codex Home 解析收敛到 internal/codexstate 的单一 helper，供 SQLite catalog 与 turn-patch storage 共用。
• managed service 渲染只持久化明确设置且已校验的 CODEX_HOME，不改变未设置时的默认环境。

检查参考

• go test ./internal/codexstate
• go test ./internal/app/daemon
• go test ./internal/app/install
• scripts/check/pre-commit.sh

收尾参考

• 使用 raw git 创建英文 conventional commit。
• 通过 ./safe-push.sh 推送任务分支。
• 创建包含 Closes #1、验证记录和文档影响的 draft PR。

执行决策

• 是否拆分：否；SQLite catalog、turn-patch storage 与 managed service 环境属于同一个 CODEX_HOME 路径合同，拆开会形成中间不一致状态。
• 当前执行单元：fork Issue Fix non-default CODEX_HOME state resolution #1。
• verifier 决策：不运行独立 verifier；该变更不涉及安全、迁移或状态机，由父执行者完成 focused tests、pre-commit 和最终 diff 复核。

当前执行单元

Review upstream draft PR kxn#905 for commit efe31edc; do not mark it ready or merge it without explicit authorization.

下一步

Inspect upstream draft PR kxn#905 checks and review feedback. Mark ready or merge only after explicit authorization for that PR.

最后一致状态

Commit efe31edc implements the shared resolution and persisted install-state contract. Focused tests, go test ./... -count=1, and scripts/check/pre-commit.sh passed. The branch was published through safe-push.sh, fork draft PR #2 and upstream draft PR kxn#905 are open, and a local install verified that install state and the daemon process preserve the selected CODEX_HOME.

未完成尾项

• Add regression tests.
• Implement shared Codex home resolution.
• Wire persisted catalog and turn-patch storage.
• Preserve CODEX_HOME in systemd and launchd definitions.
• Update user documentation.
• Run repository verification and open a draft pull request.
• Review upstream draft PR fix(codex): 支持非默认 CODEX_HOME kxn/codex-remote-feishu#905 and its checks.
• Mark ready or merge only after explicit authorization.
• Complete post-merge cleanup and close-out.

执行快照

• 当前阶段：上游 draft PR 审查停点。
• 当前执行点：上游 PR fix(codex): 支持非默认 CODEX_HOME kxn/codex-remote-feishu#905 已创建为 draft，尚未获得 ready/merge 授权。
• 已完成：根因定位、上游 Issue 非默认 CODEX_HOME 下 daemon 仍从 $HOME/.codex 读取持久状态 kxn/codex-remote-feishu#904、fork Issue Fix non-default CODEX_HOME state resolution #1、实现、回归测试、全仓验证、安全推送、本地安装验证、上游 draft PR。
• 下一步：检查上游 PR fix(codex): 支持非默认 CODEX_HOME kxn/codex-remote-feishu#905 的 checks 与 review feedback；没有明确授权不得 ready 或 merge。
• 恢复步骤：读取 Issue Fix non-default CODEX_HOME state resolution #1 与上游 PR fix(codex): 支持非默认 CODEX_HOME kxn/codex-remote-feishu#905 的最新状态，核对 HEAD efe31edc 和 CI，再按用户明确授权继续。