Add linux wallpaperengine integration

[CollieIsCute]

Summary

• Install linux-wallpaperengine-git for Arch/CachyOS through the existing paru package flow.
• Add opt-in chezmoi data and linux-wallpaperengine-start wrapper for Hyprland startup.
• Template Noctalia config so its static wallpaper layer stays enabled by default and turns off only when Wallpaper Engine arguments are configured.
• Document host-local setup via data.wallpaperEngine.arguments.
• Skip linux-wallpaperengine-git in GitHub Actions because it is a large AUR source build; real Arch/CachyOS applies still install it.

Research

• Upstream README documents Arch installation via linux-wallpaperengine-git, Steam Wallpaper Engine asset requirements, CLI syntax, and Wayland support: https://github.com/Almamu/linux-wallpaperengine
• Upstream Arch packaging confirms the binary wrapper name linux-wallpaperengine and install prefix behavior: https://github.com/Almamu/linux-wallpaperengine/blob/main/packaging/archlinux/PKGBUILD

Verification

• chezmoi execute-template --source /home/collie/.local/share/chezmoi '{{ .wallpaperEngine.enabled }} {{ len .wallpaperEngine.arguments }}'
• bash -n <(chezmoi execute-template --source /home/collie/.local/share/chezmoi < home/dot_local/bin/executable_linux-wallpaperengine-start.tmpl)
• bash -n <(chezmoi execute-template --source /home/collie/.local/share/chezmoi < home/.chezmoiscripts/run_onchange_after_0-install-packages.sh.tmpl)
• chezmoi execute-template --source /home/collie/.local/share/chezmoi < home/dot_config/noctalia/config.toml.tmpl | python -c 'import sys, tomllib; tomllib.loads(sys.stdin.read())'
• luac -p on rendered Hyprland Lua when luac is available