Add YSH rewrite for cycle_wallpaper and install Oils via nixpkgs

[Copilot]

This narrows the YSH work to the scope requested in review: add YSH from nixpkgs in alice.nix and introduce a new YSH rewrite of the wallpaper script without changing the current login shell flow or removing the existing Bash scripts.

• Add YSH from nixpkgs

  • Add oils-for-unix to /home/runner/work/dotfiles/dotfiles/home/alice.nix.

• Add a parallel YSH script

  • Introduce /home/runner/work/dotfiles/dotfiles/script/cycle_wallpaper.ysh as a YSH-side rewrite of the existing wallpaper script.
  • Keep /home/runner/work/dotfiles/dotfiles/script/cycle_wallpaper.sh in place and unchanged as the current caller target.

• Keep existing shell/setup behavior unchanged

  • Do not change the login shell.
  • Do not add tracked Oils config deployment through setup/setup.sh, setup/links.sh, or Home Manager config links.
  • Do not update README shell support messaging as part of this PR.

Example:

# existing Bash script remains
~/dotfiles/script/cycle_wallpaper.sh

# new YSH rewrite added alongside it
~/dotfiles/script/cycle_wallpaper.ysh

home.packages = with pkgs; [
  bun
  oils-for-unix
  sheldon
];

The result is an incremental YSH migration focused on script rewrites only, with no change to the current zsh-based login-shell setup.

[Uliboooo]

i planned change only scripts(e.g. cycle_wallpaper.sh).
and
don't change login shell.
and please process rewrite scripts(but don't remove bash scripts, create a new scripts for YSH script

about nix

please add YSH as nixpkgs in alice.nix.

[Copilot]

i planned change only scripts(e.g. cycle_wallpaper.sh).
and
don't change login shell....

Addressed in 6537e39. The broader YSH config/login-shell changes were reverted, oils-for-unix was added to /home/runner/work/dotfiles/dotfiles/home/alice.nix, and a new /home/runner/work/dotfiles/dotfiles/script/cycle_wallpaper.ysh was added alongside the existing Bash script without rewiring current callers.

[Uliboooo]

@copilot please merge latest change to this branch from main

[Copilot]

@copilot please merge latest change to this branch from main

Merged the latest main into this branch in 7ecb1fa. The merge was clean, the branch diff stayed scoped to the YSH changes, and targeted validation plus final automated validation passed.

[Uliboooo]

@copilot why don't write YSH scripts other than cycle?