macOS: preserve native editing keys and add optional Codex draft selection

[mrcertis]

This proposal gives macOS users native Command+A/C/V draft editing and prevents focused CLI keys such as F2 and Home from also triggering canvas actions.

Behavior

• Command+A selects the entire Codex draft with the optional frontend. Command+C copies draft selection or selected terminal output. Command+V supports text and native clipboard images.
• Enter and Shift+Enter insert a newline in the optional macOS frontend's main draft, including during startup. Only Command+Enter submits or queues. Tab completes without sending. Trust/resume/approval dialogs and embedded question editors retain their normal Enter behavior.
• Ordinary application fields keep native Command+A selection. Other terminal keys reach the focused CLI; canvas shortcuts remain available with canvas focus.
• Delayed clipboard reads are discarded after a terminal closes, exits or restarts.
• Launch-scoped Codex configuration uses --no-daemon. Successfully spawned terminals retain an unused browser capability until cleanup, avoiding expiry during delayed trust/resume dialogs. Existing authentication and one-time-use checks remain intact.

Optional frontend

Stock Codex 0.159.2 lacks whole-draft selection. The separate macOS frontend is based on official rust-v0.159.2 and requires official codex-cli 0.159.2 as its backend. The standard CanvasTTY build does not download or bundle it automatically; ordinary CLI launching remains available. Distribution and ongoing version support need maintainer review, so this remains a draft proposal. See the integration document.

Validation

• CanvasTTY: 1241 tests passed, zero failed, two skipped. Build, TypeScript checks and secret audit passed.
• Frontend: 28 focused editing/startup/launch checks passed; expanded checks reported 83 passed and one existing version-dependent header-padding snapshot failure. Scoped Clippy, Rust formatting and build passed. Launcher: 14 tests passed.
• Apple Silicon GUI: Enter and Shift+Enter produced unsent three-line drafts during and after startup; Command+A/C preserved the complete text and both newlines. Shortcuts help displays Command+Enter for sending and Enter for a new line. No real task was submitted; submission and queueing were checked in mocked tests.

Intel packaging and Windows/Linux execution remain unverified. The frontend README records its existing full-suite limitations.