refactor(common): move package search into shared base

- Install nix-search-cli through common.nix
- Remove its development module entry and update documentation

modules/common.nix

@@ -12,6 +12,8 @@
   };
   nixpkgs.config.allowUnfree = true;
 
+  environment.systemPackages = [ pkgs.nix-search-cli ];
+
   networking.networkmanager.enable = true;
   time.timeZone = "Africa/Tunis";
   i18n.defaultLocale = "en_US.UTF-8";

modules/development.nix

@@ -10,7 +10,6 @@
     tmux
     ripgrep
     fd
-    nix-search-cli
     duf
     dust
     killall