fix: Remove incorrect ./parts/fleet-data.nix import from flake.nix and use correct flake-parts structure

parts/formatter.nix

@@ -0,0 +1,9 @@
+# Formatter configuration for flake-parts
+{ ... }:
+{
+  perSystem =
+    { pkgs, ... }:
+    {
+      formatter = pkgs.nixfmt-rfc-style;
+    };
+}

parts/lib.nix

@@ -0,0 +1,5 @@
+# Library functions for flake-parts
+{ inputs, ... }:
+{
+  flake.lib = import ../lib { inherit inputs; };
+}

parts/nixos-configurations.nix

@@ -0,0 +1,12 @@
+# NixOS configurations generated from fleet
+{ inputs, self, lib, pkgs, config, ... }:
+{
+  imports = [
+    (import ../fleet/fleet-option.nix { inherit inputs lib pkgs config; })
+  ];
+  flake.nixosConfigurations =
+    let
+      fleet = self.lib.mkFleet { inherit inputs lib pkgs config; };
+    in
+    fleet.nixosConfigurations;
+}

parts/nixos-modules.nix

@@ -0,0 +1,5 @@
+# Expose host type modules and installer modules for external use
+{ inputs, ... }:
+{
+  flake.nixosModules = import ../installer/modules.nix { inherit inputs; };
+}

parts/packages.nix

@@ -0,0 +1,27 @@
+# Build artifacts (ISOs, LXC containers, etc.)
+{
+  inputs,
+  self,
+  lib,
+  config,
+  ...
+}:
+{
+  perSystem =
+    { system, ... }:
+    lib.mkIf (system == "x86_64-linux") {
+      packages =
+        let
+          fleet = self.lib.mkFleet { inherit inputs lib config; };
+          artifacts = import ../installer/artifacts.nix {
+            inherit
+              inputs
+              fleet
+              self
+              system
+              ;
+          };
+        in
+        artifacts;
+    };
+}

parts/templates.nix

@@ -0,0 +1,5 @@
+# Templates for external configurations
+{ ... }:
+{
+  flake.templates = import ../templates;
+}