Replace Rofi with Walker as application launcher

Walker (GTK4 + Elephant backend) replaces rofi-lbonn-wayland-git as the
central launcher and menu framework.

Native Walker providers replace 5 custom rofi scripts:
- App launcher (desktopapplications provider)
- Clipboard (clipboard provider, replaces cliphist frontend)
- Bluetooth (bluetooth provider, replaces bluetoothctl script)
- Volume/audio (wireplumber provider)
- Sink switcher (wireplumber provider)

3 scripts ported to Walker dmenu mode:
- moonarch-vpn (nmcli)
- moonarch-cpugov (auto-cpufreq)
- moonarch-sink-switcher (pactl)

Settings menu (moonarch-setmen) removed — apps are findable via Walker
app search directly.

Walker theme (gtk-inherit) inherits all colors from the active GTK4
theme instead of hardcoding Catppuccin values.

Walker and Elephant run as systemd user services for instant startup.

Also standardizes GTK theme to Colloid-Grey-Dark-Catppuccin across all
config files (was inconsistent between gsettings and file configs).

Old rofi configs preserved in legacy/rofi/ for reference.

legacy/rofi/bin/moonarch-volume

@@ -0,0 +1,122 @@
+#!/usr/bin/env bash
+# ABOUTME: Rofi-based volume control applet for managing speakers and microphone.
+# ABOUTME: Provides mute toggles, sink switching, mixer access, and NoiseTorch.
+
+## Author  : Aditya Shakya (adi1090x)
+## Github  : @adi1090x
+#
+## Applets : Volume
+
+theme="/etc/xdg/rofi/themes/volume.rasi"
+
+# Volume Info
+mixer="`amixer info Master | grep 'Mixer name' | cut -d':' -f2 | tr -d \',' '`"
+speaker="`amixer get Master | tail -n1 | awk -F ' ' '{print $5}' | tr -d '[]'`"
+mic="`amixer get Capture | tail -n1 | awk -F ' ' '{print $5}' | tr -d '[]'`"
+
+active=""
+urgent=""
+
+# Speaker Info
+amixer get Master | grep '\[on\]' &>/dev/null
+if [[ "$?" == 0 ]]; then
+	active="-a 1"
+	stext='Mute Speaker'
+	sicon='󰓃'
+else
+	urgent="-u 1"
+	stext='Unmute Speaker'
+	sicon='󰓄'
+fi
+
+# Microphone Info
+amixer get Capture | grep '\[on\]' &>/dev/null
+if [[ "$?" == 0 ]]; then
+    [ -n "$active" ] && active+=",3" || active="-a 3"
+	mtext='Mute Mic'
+	micon=''
+else
+    [ -n "$urgent" ] && urgent+=",3" || urgent="-u 3"
+	mtext='Unmute Mic'
+	micon=''
+fi
+
+currentsink=$(pactl get-default-sink)
+currentsource=$(pactl get-default-source)
+
+
+# Theme Elements
+prompt="Speaker: $sicon   Mic: $micon "
+mesg="$mixer        Speaker: $speaker        Mic: $mic"
+
+list_col='6'
+list_row='3'
+win_width='670px'
+
+# Options
+option_1="$micon $mtext		›$currentsource"
+option_2="$sicon $stext		›$currentsink"
+option_3="󱡫 Sink Switcher"
+option_4=""
+option_5=" Mixer"
+option_6="󰍯 Noise Torch"
+
+
+# Rofi CMD
+		#-theme-str "listview {columns: $list_col; lines: $list_row;}" \
+rofi_cmd() {
+	rofi -theme-str "window {width: $win_width;}" \
+		-dmenu \
+		-p "$prompt" \
+		-mesg "$mesg" \
+		${active} ${urgent} \
+		-markup-rows \
+		-theme ${theme}
+}
+
+# Pass variables to rofi dmenu
+run_rofi() {
+	echo -e "$option_1\n$option_2\n$option_3\n$option_4\n$option_5\n$option_6" | rofi_cmd
+}
+
+# Execute Command
+run_cmd() {
+	if [[ "$1" == '--opt3' ]]; then
+		#amixer -Mq set Master,0 5%+ unmute
+		moonarch-sink-switcher
+	elif [[ "$1" == '--opt2' ]]; then
+		amixer set Master toggle
+	elif [[ "$1" == '--opt4' ]]; then
+		amixer -Mq set Master,0 5%- unmute
+
+	elif [[ "$1" == '--opt1' ]]; then
+		amixer set Capture toggle
+	elif [[ "$1" == '--opt5' ]]; then
+		pavucontrol
+	elif [[ "$1" == '--opt6' ]]; then
+		noisetorch
+	fi
+}
+
+# Actions
+chosen="$(run_rofi)"
+case ${chosen} in
+    $option_1)
+		run_cmd --opt1
+        ;;
+    $option_2)
+		run_cmd --opt2
+        ;;
+    $option_3)
+		run_cmd --opt3
+        ;;
+    $option_4)
+		run_cmd --opt4
+        ;;
+    $option_5)
+		run_cmd --opt5
+        ;;
+	$option_6)
+		run_cmd --opt6
+        ;;
+esac