0.18.0 — Remove Jetify Cloud features

What's Changed

Remove jetify cloud functionality from devbox. These features are being sunsetted and will no longer work.

💥 Breaking Changes

• The Jetify Nix cache is gone — the devbox cache command tree (upload/copy, configure, credentials, enable, info) is removed, and nix build no longer receives extra substituters. Package lookups now query only the public https://cache.nixos.org. The nightly cache-upload workflow goes with it, by @mikeland73 (#2940)
• Jetify Cloud secrets are gone — the devbox secrets command tree (alias envsec) is removed, along with devbox auth whoami, whose implementation lived there. Projects that still set env_from to jetify-cloud (or the legacy envsec / jetpack-cloud spellings) keep starting: Devbox now warns and skips those secrets instead of failing, so you don't have to edit an existing devbox.json first. Move those secrets into a .env file, by @mikeland73 (#2941)
• devbox global push / pull now require an argument — the no-argument form synced your global profile to Jetify-hosted storage and has been removed. Every source that needs no account still works: push takes a git repo, pull takes a git repo, an http(s) archive, a devbox.json URL, or a local path. Cobra rejects the bare form outright, so the failure is immediate rather than a confusing cloud error, by @mikeland73 (#2942)
• devbox auth is gone — login, logout, and tokens new are removed, along with the browser OAuth flow, the session stored under $XDG_CACHE_HOME/jetify/auth, and the DEVBOX_API_TOKEN exchange. Telemetry no longer reads any token from disk: user_id now derives only from the GITHUB_USER_NAME hash and org_id is dropped. DO_NOT_TRACK and everything else about telemetry is unchanged, by @mikeland73 (#2943)

🐛 Bug Fixes

• The zig example builds on macOS again — zig is now pinned at 0.16.0 (it was pinned at 0.11.0, whose Mach-O linker emits binaries modern dyld refuses to load), and build.zig is migrated to the current root_module API. This test gated the whole release pipeline, by @mikeland73 (#2951)

🧹 Maintenance

• Dropped the dependencies left over from the account features — the AWS SDK v2 modules, envsec, typeid, go-jose, oauth2, heredoc, and tablewriter, by @mikeland73 (#2944)
• Scripted the release flow behind devbox run draft-release / publish-release, which fixes the draft-versus-tag ordering that produced 0.17.5's bare-SHA release notes and broke the Docker build on 0.17.3 and 0.17.5. Also fixes Sentry release naming, prereleases overwriting the Docker latest tag, and a fail-fast test matrix that cancelled every shard when one failed, by @mikeland73 (#2952) and (#2954)

Full Changelog: 0.17.5...0.18.0