feat: simplify flake-parts imports

flake/apps.nix

@@ -0,0 +1,32 @@
+{ self, ... }:
+{
+  perSystem = { system, ... }:
+    let
+      mkApps = system: names: self: builtins.listToAttrs (map
+        (name: {
+          inherit name;
+          value = {
+            type = "app";
+            program = "${self.packages.${system}.${name}}/bin/${name}";
+            meta = {
+              description = "Custom app ${name}.";
+            };
+          };
+        })
+        names);
+
+      appNames = [
+        "swarsel-bootstrap"
+        "swarsel-install"
+        "swarsel-rebuild"
+        "swarsel-postinstall"
+      ];
+
+      appSet = mkApps system appNames self;
+    in
+    {
+      apps = appSet // {
+        default = appSet.swarsel-bootstrap;
+      };
+    };
+}