Make program integrations conditional on shell

modules/core/packages/programs.nix

@@ -1,11 +1,14 @@
-_: {
+{shell, ...}: {
   programs = {
     nano.enable = true;
     hyprland = {
       enable = true;
       withUWSM = false;
     };
-    fish.enable = true;
+    fish.enable =
+      if shell == "fish"
+      then true
+      else false;
     dconf.enable = true;
     seahorse.enable = true;
     fuse.userAllowOther = true;

modules/core/user.nix

@@ -43,7 +43,10 @@
         username = "${username}";
         homeDirectory = "/home/${username}";
         stateVersion = "25.11";
-        shell.enableFishIntegration = true;
+        shell.enableFishIntegration =
+          if shell == "fish"
+          then true
+          else false;
       };
     };
   };