feat(install): idempotent per-host package installer with host-gated enablement

packages/aur.pkgs

@@ -0,0 +1,8 @@
+# packages/aur.pkgs — AUR-only desired state, installed via yay (bootstrapped
+# from the cachyos repo by install.sh). pkgbase names; runtime resolution by yay.
+
+oh-my-zsh-git       # system-wide oh-my-zsh at /usr/share/oh-my-zsh; sourced by .zshrc guard
+herdr-bin           # AI-agent terminal workspace manager (prebuilt binary)
+proton-pass         # Proton Pass desktop client
+handy-bin           # Handy voice dictation (AppImage repackaged as pkg)
+typora              # markdown editor