fix(macos): run signed Node across Rosetta launchers

[ImcLiuQian]

Change-Id: I06a06d7b705bbd3706ec3798125e6a77a05f387f

Summary / 摘要

• Fix legacy macOS launchers that run under Rosetta while the official ChatGPT bundle ships an arm64-only Node.
• Keep the fixed-path code-signature and OpenAI Team ID gates, then prove compatibility by executing the validated Node instead of comparing it with the parent shell architecture.
• Add an Apple Silicon + Rosetta signed-runtime regression and a static guard against launcher-architecture prechecks.
• Align the runtime contract documentation.

Type / 类型

• Bug fix / 缺陷修复
• Feature / 新功能
• Docs / 文档
• Theme / CSS / visual / 主题或视觉
• Scripts / install / restore / 脚本或安装恢复
• Chore / 杂项

Platform / 平台

• macOS
• Windows
• Both / 双平台
• Docs / repo only / 仅文档或仓库元数据

Self-check / 自测

Docs-only / 仅文档

• Links and wording reviewed / 已检查链接与表述

macOS (when code under macos/ changes)

• macos/tests/run-tests.sh passed / 已通过
• Doctor (optional): macos/scripts/doctor-macos.sh
• Live verify (if inject/CSS/start path): verify-dream-skin-macos.sh or Desktop Verify
• Restore / re-apply smoke (if install/restore/start changed) / 若改了安装恢复启动则做过恢复再应用

Windows (when code under windows/ changes)

• Relevant install / start / verify / restore scripts exercised / 已按改动跑过对应脚本
• Environment noted below (OS build, Codex source) / 下方注明环境

User-facing / 用户可见变更

• Updated macos/CHANGELOG.md (and macos/VERSION if release-worthy) / 已更新 changelog（发版时再 bump VERSION）
• N/A — no user-facing change / 无用户可见变更

Security / 安全

• Does not modify official Codex install / asar / signatures / 未修改官方安装与签名
• Does not silently write API Base URL or keys / 未静默写入 API Base URL 或 Key
• CDP remains loopback-oriented (127.0.0.1) where applicable / CDP 仍仅本机回环（如适用）

Notes / 补充

• Real Apple Silicon regression: an x86_64 Rosetta shell successfully validated and executed the official arm64 Node v24.14.0 and recorded the validated runtime identity.
• Bash syntax, git diff --check, renderer, Safe CSS, staging, package, and ZIP-boundary regressions passed before an unrelated fixture.
• The complete local wrapper then stopped at the bounded-community HTTP Swift fixture because the local Command Line Tools compiler does not match its macOS SDK and the sandbox cannot write the Clang module cache. Swift compilation was not retried locally; PR CI remains the gate.
• Exact installed legacy-engine payload passed the same Rosetta validation and preserved the active theme hashes.
• No version bump or Release publication is included.