Add consistent --help/-h argument handling to update-doomemacs.sh,
rotate-wallpaper.sh, and upgrade.sh scripts. Each script now displays
usage information and a description of what it does.
update-claude-code already had --help support.
Creates update-doomemacs.sh script that:
- Fetches latest commit SHA from doomemacs/doomemacs repo
- Automatically detects the default branch
- Updates both rev and sha256 in home/roles/emacs/default.nix
- Works from anywhere in the repo using git rev-parse
Also adds a flake app so it can be run with:
nix run .#update-doomemacs
