[codex] Integrate Communique release notes

[ThomasK33]

Summary

Integrates Communique into the existing release flow without changing the runtime TypeScript/native API surface.

• Adds pinned Communique tooling, repo-specific communique.toml, and a CHANGELOG.md scaffold included in the npm package.
• Adds release PR changelog automation for internal release/v* branches targeting main.
• Updates publish automation to generate editorialized release notes, publish npm through the existing Trusted Publishing path, then create or update the GitHub Release with install/platform notes.
• Uses defensive Node helper scripts for release branch/version checks and GitHub Release note parsing/update assertions.
• Drops macOS x64 CI/prebuild/release support so the release matrix targets Linux x64, Linux arm64, and macOS arm64.

Validation

• actionlint .github/workflows/ci.yml .github/workflows/release-prebuilds.yml .github/workflows/publish.yml .github/workflows/release-changelog.yml
• node --check .github/scripts/prepare-release-changelog.mjs && node --check .github/scripts/create-or-update-github-release.mjs
• node .github/scripts/prepare-release-changelog.mjs HEAD
• communique --version
• MISE_LOCKED=1 mise install communique --dry-run
• npm pack --dry-run
• PR checks passed for ci (linux-x64), ci (linux-arm64), and ci (macos-arm64).

Known local blocker

mise run ci and mise run release-prebuilds both fail locally at the existing npm run build:libghostty step with Zig/macOS SDK undefined symbol linker errors before the new release integration runs. The local SDK path and Xcode selection resolve with xcrun --show-sdk-path and xcode-select -p, so this appears to be a local Zig/Xcode linker issue rather than a regression in this PR.