macbook: drop helium, add browsh

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

hosts/FredOS-Macbook.nix

@@ -5,7 +5,7 @@
     environment.systemPackages = with pkgs; [
       tlp
       spotify
-      vesktop
+      discordo
       faugus-launcher
       mission-center
       vlc
@@ -15,6 +15,11 @@
       woeusb
       vscodium
       cmatrix
+
+      # TTY browsing: browsh drives a headless firefox and renders it to the
+      # terminal, so firefox has to be on PATH — it is not wrapped in.
+      browsh
+      firefox
     ];
 
     programs.geary.enable = true;