Restructure flake.nix for a simpler config for building different images off the same NixOS config.

nix/configuration/roles/shipwright/default.nix

@@ -17,32 +17,27 @@
     };
   };
 
-  config = lib.mkIf config.me.shipwright.enable (
-    lib.mkMerge [
-      {
-        allowedUnfree = [ "shipwright" ];
-      }
-      (lib.mkIf config.me.graphical {
-        environment.systemPackages = with pkgs; [
-          shipwright
+  config = lib.mkIf (config.me.shipwright.enable && config.me.graphical) {
+    allowedUnfree = [ "shipwright" ];
+
+    environment.systemPackages = with pkgs; [
+      shipwright
+    ];
+
+    # TODO perhaps install ~/.local/share/soh/shipofharkinian.json
+
+    environment.persistence."/persist" = lib.mkIf (config.me.mountPersistence) {
+      hideMounts = true;
+      users.talexander = {
+        directories = [
+          {
+            directory = ".local/share/soh";
+            user = "talexander";
+            group = "talexander";
+            mode = "0755";
+          }
         ];
-
-        # TODO perhaps install ~/.local/share/soh/shipofharkinian.json
-
-        environment.persistence."/persist" = lib.mkIf (!config.me.buildingIso) {
-          hideMounts = true;
-          users.talexander = {
-            directories = [
-              {
-                directory = ".local/share/soh";
-                user = "talexander";
-                group = "talexander";
-                mode = "0755";
-              }
-            ];
-          };
-        };
-      })
-    ]
-  );
+      };
+    };
+  };
 }