fix(nixos): deploy from source checkout

Replace target-checkout deployment with source-built closure import and activation. Allow SteamCMD game services to stay configured without auto-starting, and disable Palworld auto-start on Pikachu.

configs/nixos/modules/shell/fish/default.nix

@@ -99,7 +99,7 @@ in
           };
 
           deploy-to = {
-            description = "Deploy the current dotfiles branch to a host through target-local nixos-rebuild";
+            description = "Build the current checkout locally, import it on a host, and activate it";
             body = builtins.readFile ./functions/deploy-to.fish;
           };