quickshell: replace macOS-style shell with standalone overview module

Swap the illogical-impulse-derived components for the upstream
quickshell-overview standalone module, update Hyprland keybinds
(Super+Tab overview, rofi launcher), refresh foot colors and
starship theme, and adjust related host/module wiring.

modules/apps/terminal.nix

@@ -1,7 +1,7 @@
 { pkgs, ... }:
 
 {
-    # Foot terminal is configured and managed via Home Manager (home/foot.nix)
+    # Terminal is managed elsewhere; system-level CLI helpers live here.
     environment.systemPackages = with pkgs; [
         zoxide
         fzf