omarchy update — separate download and apply phases for unstable Internet connections

[AL-ABYADH]

Problem

omarchy update downloads and applies all updates in a single transaction. On an unstable connection a drop mid-transaction aborts the whole run, and surviving an interrupted pacman -Syu (or a half-updated system with mixed package versions) can leave the system half-broken. This has happened to me more than once; I know others with the same problem.

Requested change

Split the update into two steps so that nothing touches the system until everything is downloaded:

1. Download phase — fetch all packages (system, AUR, mise) into the local cache, with nothing applied and the system untouched. Interrupted downloads must be resumable so the phase can be retried until it completes.
2. Apply phase — install the already-downloaded updates from cache, working fine offline, since the download step already ran.

Because a dropped connection may also interrupt the reuse-based logic, the request explicitly wants:

• the download phase to be safe to run many times (it should be idempotent / resumable), and
• the apply phase to never re-initiate a network download.

Suggested implementation surface

Pacman already supports this:

• sudo pacman -Syu --downloadonly --noconfirm downloads everything into /var/cache/pacman/pkg (partial transfers are kept as .part and resume on the next run).
• A subsequent plain pacman -Syu installs those same packages from the local cache without needing the network.
• yay -Sua --downloadonly covers AUR analogously; mise tools are downloaded releases and would need the same staging.

A UX like omarchy update --download-only, or omarchy update dowload / omarchy update apply, or a flag that runs download-only by default for users who opt in, would solve this. The key guarantee is: system state never changes until the download step has fully succeeded.

This is a feature suggestion, not a bug report. I'm happy to help test the download/apply split once a first version exists.