Allow global exec flags after resume and fix CI codex build/timeout

[fjord-oai]

Motivation

• Bring codex exec resume to parity with top‑level flags so global options (git check bypass, json, model, sandbox toggles) work after the subcommand, including when outside a git repo.
• Fix CI’s musl build for the CLI and avoid premature 10‑minute cancellations.

Description

• CI: build the correct crate (-p codex-cli --bin codex) and extend the workflow timeout to 30 minutes in .github/workflows/ci.yml.
• Exec CLI: mark --skip-git-repo-check, --json, --model, --full-auto, and --dangerously-bypass-approvals-and-sandbox as global so they’re accepted after resume.
• Tests: add exec_resume_accepts_global_flags_after_subcommand to verify those flags work when passed after resume.

Testing

• just fmt
• cargo test -p codex-exec (pass; ran with elevated perms to allow network/port binds)
• Manual: exercised codex exec resume with global flags after the subcommand to confirm behavior.

[github-actions]

All contributors have signed the CLA ✍️ ✅
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[fjord-oai]

I have read the CLA Document and I hereby sign the CLA

[fjord-oai]

recheck