Replace caelestia shell with Waybar and Walker

Remove caelestia-shell/cli inputs and prune corresponding flake.lock
entries. Update Hyprland keybindings to use walker, grimblast and
Waybar, use loginctl for locking and pkill/waybar for restart. Add
new home/system modules for waybar and walker and enable them in
host configs. Delete obsolete INSTALL-laptop.md.

flake.nix

@@ -28,14 +28,7 @@
       url = "github:nix-community/home-manager";
       inputs.nixpkgs.follows = "nixpkgs";
     };
-    caelestia-shell = {
-      url = "github:caelestia-dots/shell";
-      inputs.nixpkgs.follows = "nixpkgs";
-    };
-    caelestia-cli = {
-      url = "github:caelestia-dots/cli";
-      inputs.nixpkgs.follows = "nixpkgs";
-    };
+
 
     # Server
     nixarr.url = "github:rasmus-kirk/nixarr";