refactor(dotfiles): rename system/ to common/ and remove unused configs

Rename dotfiles/system to dotfiles/common for clarity - indicates
shared dotfiles used across all desktop environments (DWM, Hyprland).

Removed config directories for uninstalled applications:
- ghostty (using different terminal)
- lf (using ranger instead)
- mopidy (using mpd instead)
- nitrogen (X11-only, obsolete for Wayland)
- pychess (not installed)
- JetBrains (not installed via archsetup)
- youtube-dl (using yt-dlp with different config location)

Kept audacious config for potential future use.

Updated all references in archsetup, CLAUDE.md, todo.org, and
validation.sh.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

1 files changed, 0 insertions, 47 deletions

diff --git a/dotfiles/system/.zshrc.d/arch-downgrade.sh b/dotfiles/system/.zshrc.d/arch-downgrade.sh
deleted file mode 100644
index f1d01a7..0000000
--- a/dotfiles/system/.zshrc.d/arch-downgrade.sh
+++ /dev/null
@@ -1,47 +0,0 @@
-# arch-downgrade.sh
-# Craig Jennings <c@cjennings.net>
-# Downgrade Arch packages with fzf (zsh only)
-
-# Config:
-#   export DG_HELPER=pacman   # or yay, paru, etc.
-#   export DG_FZF_OPTS="..."  # optional extra fzf flags
-
-dg() {
-    emulate -L zsh
-    set -u
-    set -o pipefail
-
-    local helper="${DG_HELPER:-pacman}"
-
-    # Check dependencies
-    for cmd in "$helper" fzf sudo downgrade awk sort; do
-        if ! command -v "${cmd%% *}" >/dev/null 2>&1; then
-            print -u2 -- "Missing dependency: $cmd"
-            return 1
-        fi
-    done
-
-    # List explicitly installed packages
-    local selection
-    selection="$(
-        "$helper" -Qe 2>/dev/null \
-          | fzf --no-multi \
-                --prompt="Pick package to downgrade > " \
-                --height=80% \
-                --reverse \
-                --delimiter=' ' \
-                --preview-window=right:60%:wrap \
-                --preview "$helper -Qi {1} 2>/dev/null || $helper -Si {1}" \
-                ${DG_FZF_OPTS:-}
-    )"
-
-    [[ $? -ne 0 || -z "$selection" ]] && return 0
-
-    local pkg
-    pkg="$(print -r -- "$selection" | head -n1 | awk '{print $1}')"
-
-    if ! sudo downgrade "$pkg"; then
-        print -u2 -- "Downgrade failed for $pkg"
-        return 1
-    fi
-}