Don't install GUI apps via Home Manager

Ghostty isn't currently available in nixpkgs and I want faster updates for Zed
than nixpkgs can provide. Importantly they're both GUI apps, which Home Manager
isn't very good at managing anyway. In both cases we can continue to leverage
Home Manager for configuration and in Zed's case, if/when the configuration
format changes and becomes incompatible, we can cross that bridge.

home/editor.nix

@@ -1,9 +1,6 @@
-{
-  lib,
-  pkgs,
-  pkgs-unstable,
-  ...
-}:
+# Zed's installation is managed outside of Nix.
+
+{ lib, pkgs, ... }:
 
 {
   programs.helix = {
@@ -13,7 +10,7 @@
 
   programs.zed-editor = {
     enable = true;
-    package = pkgs-unstable.zed-editor;
+    package = pkgs.emptyDirectory;
     extensions = [
       "biome"
       "dockerfile"

home/terminal.nix

@@ -1,3 +1,5 @@
+# Ghostty's installation is managed outside of Nix.
+
 { ... }:
 
 {