control centre, notification overhaul, and cleanup

One centred rofi panel (super+x, or the gear in the bar) now drives network,
bluetooth, audio, WireGuard, display, notifications, clipboard, emoji,
screenshots, wallpaper, the particle layer, the bar and power. The separate
per-function menus are gone.

dunst: icons and images were disabled outright (icon_position=off,
max_icon_size=0). Now icons resolve through Papirus, images render, progress
bars are styled, notifications gap and stack, and fullscreen windows are not
covered unless the message is critical. Volume up/down never notified at all;
they now show a stacking OSD with a progress bar.

Removed things that were broken or belonged to whoever this rice came from:
- vpn-launcher.sh (mullvad/openvpn) and dc-multivpn
- audio/bluetooth/network/power rofi menus, folded into the control centre
- untar-all, unzip-all, resetxdgportal (unreferenced)
- a sxhkd binding hardcoded to /home/sarthak/projects/scribe
- clipboard-manager.sh keyed off XDG_SESSION_TYPE, which is 'tty' here, so it
  only ever printed a Russian error; rewritten on greenclip
- toggle-bar.sh was bound to super+b but did not exist; written

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Cn3dHfbgNYdbZvzb1b3GQt

.config/scripts/toggle-bar.sh

@@ -0,0 +1,7 @@
+#!/usr/bin/env bash
+# Show or hide polybar. Bound to super + b.
+if pgrep -x polybar >/dev/null 2>&1; then
+    pkill -x polybar
+else
+    sh "$HOME/.config/polybar/launch.sh" >/dev/null 2>&1 &
+fi