Package and document the signed macOS application

[codeacme17]

Tracks #1.

Summary

Package the proven source-mode runtime as a signed macOS application with a thin Tauri supervisor and documented installation, compatibility, security, and recovery behavior.

Scope

• Add a Tauri 2 shell only after the source-mode Host Adapter and release gate are stable.
• Bundle/supervise the Node runtime, built Git Surface, local server, and Codex Host Adapter without reimplementing Repository Engine behavior in Rust.
• Start on an ephemeral loopback port, pass launch secrets in memory where possible, monitor health, and tear down server/CDP connections on exit.
• Prefer a dedicated owned Codex profile/instance for the supported injection path.
• Add macOS signing/notarization, versioning, install/uninstall, crash recovery, and diagnostic collection that preserves redaction.
• Document supported Codex/Git/macOS versions, the unsupported CDP integration, trusted-local-process risk, standalone fallback, and troubleshooting.
• Ensure uninstall does not modify or delete user repositories, Worktrees, Codex projects, credentials, or Git configuration.

Acceptance criteria

• A clean supported macOS machine can install, launch, open the Codex Git page, use the standalone fallback, quit, relaunch, and uninstall using documented steps.
• The package does not modify Codex application bundles/files or duplicate Git business logic.
• Runtime children and loopback listeners terminate after normal quit and recover after a crash/relaunch.
• Signing/notarization verification passes for the release artifact.
• Documentation clearly states compatibility and local CDP security boundaries.
• The packaged build passes the same AC-01–24 gate as source mode.

Out of scope

• Auto-update service, App Store distribution, Windows/Linux packaging, cloud accounts, telemetry, or a remote backend.

Dependencies

• Prove the Codex sidebar and standalone Host Adapters #4, Implement the versioned loopback protocol and security boundary #5, and Enforce the MVP acceptance, performance, accessibility, and security gate #16.

Verification

• Clean-machine install/uninstall tests, process/listener teardown checks, signature/notarization validation, crash recovery, and the complete packaged release gate.