Add deferred Codex update controls and eight-hour checks

[lynnswap]

Purpose

Let users schedule a Codex update after current reviews, while new requests wait inside ReviewMonitor. Add startup and eight-hour update checks plus a shared manual check in Settings.

Changes

• Connect the update dialog to the Store update API with deferred and immediate choices. Show waiting, updating, restarting, and runtime-retry states in the sidebar toolbar.
• Anchor automatic checks to application startup using a continuous clock. Join overlapping checks, skip missed intervals after sleep, and perform one check after installation.
• Add Settings → Updates with checking, available, up-to-date, unsupported, and failure states plus the last check time. A manual check never starts installation.
• Ignore the CLI's startup-check preference for Monitor checks, and preserve version-probe errors instead of presenting them as up to date.
• Remove the application relaunch helper and failed-update launch argument. On quit, stop checking before Store shutdown and join startup afterward.
• Add Store-driven update previews and settings-state previews, with updated usage and ownership documentation.

Testing

• swift test --build-system swiftbuild --no-parallel: 1,254 tests passed.
• ReviewMonitor xcodebuild test, macOS arm64, signing disabled, -skipMacroValidation: 44 tests passed.
• Manual-clock tests cover startup, eight-hour boundaries, intervening manual checks, sleep catch-up, and overlapping checks during installation.
• UI tests cover waiting, installation, failure/retry, and resumed reviews through the actual Store flow with a preview backend. App tests cover shared Settings state, both dialog choices, shutdown ordering, errors, and recovery without reinstallation.
• A read-only check of the installed CLI with check_for_update_on_startup=false still returned current update information.
• Local Codex review against main: AA30B898-C740-4EF4-8C60-AD0FB71DF9D4, completed with no findings.
• Preview sources compile. Xcode Canvas rendering remains unverified because StructuredQueries macros require renewed approval.

Closes #385. Part of #382.

[chatgpt-codex-connector]

Codex Review Summary

This comment shows the latest Codex review activity on this pull request.

Review	Status	Commit	Review trigger
📝 Code Review	✅ Completed 2026-09-26T09:24:46.829951Z	4d7c3da	PR opened

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