refactor: group stow packages into common, mac and kde

Split the packages by platform so each app stays an opt-in Stow package
under common/, mac/ or kde/. KDE gets its own Fastfetch, Helium and
Spectacle packages, and darwin-breeze becomes kde/theme. The READMEs
document stowing a whole group as well as individual packages.

kde/theme/apply.sh

@@ -0,0 +1,49 @@
+#!/usr/bin/env bash
+# Regenerate the app themes from the color scheme and apply Darwin Breeze.
+#
+# Run `stow -d kde -t "$HOME" theme` from the repo root first.
+set -euo pipefail
+
+here="$(cd "$(dirname "$0")" && pwd)"
+data="${XDG_DATA_HOME:-$HOME/.local/share}"
+
+if [ ! -e "$data/color-schemes/DarwinBreezeDark.colors" ]; then
+    echo 'DarwinBreezeDark.colors is not installed; run: stow -d kde -t "$HOME" theme' >&2
+    exit 1
+fi
+
+python3 -I "$here/build.py"
+
+plasma-apply-lookandfeel --apply dev.trivk.darwinbreeze.dark
+
+# plasma-apply-colorscheme skips a scheme that is already active, so edits
+# to the .colors file would not be picked up. Bounce through stock Breeze.
+plasma-apply-colorscheme BreezeClassic >/dev/null
+plasma-apply-colorscheme DarwinBreezeDark >/dev/null
+
+# Drop the line under the title bar so it blends into the toolbar.
+kwriteconfig6 --file breezerc --group Windeco --key DrawTitleBarSeparator false
+
+# A wallpaper-derived accent color would override the blue from the scheme.
+kwriteconfig6 --file kdeglobals --group General --key AccentColor --delete
+kwriteconfig6 --file kdeglobals --group General --key accentColorFromWallpaper false
+
+qdbus6 org.kde.KWin /KWin reconfigure 2>/dev/null \
+    || dbus-send --session --type=signal /KWin org.kde.KWin.reloadConfig
+
+# T3 Code skips symlinked theme files, so publish a copy instead of stowing it.
+t3="$(command -v t3 || echo "$HOME/.t3/bin/t3")"
+if [ -x "$t3" ]; then
+    "$t3" theme set "$here/t3/darwin-breeze.json" >/dev/null
+fi
+
+# VS Code only loads themes from installed extensions. --force reinstalls the
+# same version, so color changes land without a version bump.
+if command -v code >/dev/null; then
+    code --install-extension "$here/vscode/darwin-breeze.vsix" --force >/dev/null 2>&1
+fi
+
+echo "Applied Darwin Breeze"
+if pgrep -x helium >/dev/null; then
+    echo "Restart Helium to pick up its theme"
+fi