[Wangnov]

Summary

• serialize codex-threadripper write operations with a shared lock
• keep rollout first-line provider updates length-preserving and in-place with fsync; skip rollouts that would require first-line growth instead of replacing files Codex may still be writing
• repair watch-mode rollout drift after SQLite rows change
• honor valid CODEX_HOME before falling back to HOME/.codex, and fail fast for invalid non-empty CODEX_HOME
• keep prerelease tags out of stable npm/Homebrew workflows and add CI syntax coverage for the npm matrix script

Verification

• cargo fmt --check
• cargo test
• cargo clippy --all-targets --all-features -- -D warnings
• node --check scripts/build-npm-matrix.mjs
• python -m py_compile scripts/smoke_release.py
• actionlint .github/workflows/*.yml