ci: rework flake integration

Now Use flake part and integrate a build system using nix package building and treefmt-nix as a flake-part module

flake.nix

@@ -1,68 +1,24 @@
 {
-  description = "Development shell for Personal blog";
-  
+  description = "Nix flake for my personal blog";
+
   inputs = {
-    nixpkgs.url = "github:nixos/nixpkgs/nixos-23.11";
-    flake-utils = {
-      url = "github:numtide/flake-utils";
-    };
+    nixpkgs.url = "nixpkgs/nixos-unstable";
+    flake-parts.url = "github:hercules-ci/flake-parts";
+    treefmt-nix.url = "github:numtide/treefmt-nix";
   };
 
-  outputs = { nixpkgs , flake-utils, ... }: flake-utils.lib.eachDefaultSystem (system:
-    let
-      pkgs = import nixpkgs {
-        inherit system;
-      };
-      pelicanplugins-neighbors = ( with pkgs; stdenv.mkDerivation {
-        pname = "pelicanplugins-neighbors";
-        version = "1.2.0";
-        src = pkgs.fetchFromGitHub {
-          owner = "pelican-plugins";
-          repo = "neighbors";
-          rev = "60649ac6f3494d01a37b9c6d3d455f9dc2502d55";
-          hash = "sha256-c6etuRqve9xj6NhGRAim2A0ae8xv6mI/yez+suQuZ8U=";
-        };
-        installPhase = ''
-          cp -r $src/pelican/plugins/neighbors $out
-        '';
-      });
-      pelicanplugins-md_include = ( with pkgs; stdenv.mkDerivation {
-        pname = "pelicanplugins-md_include";
-        version = "1.0.4";
-        src = pkgs.fetchFromGitHub {
-          owner = "pelican-plugins";
-          repo = "markdown-include";
-          rev = "df0b3e55c45471283ca62d6e157b61a8caa35e37";
-          hash = "sha256-y0dIvyEYLbYqkm+6yJOUYI3apzEMJ/N/JUwWTqjdsNg=";
-        };
-        installPhase = ''
-          cp -r $src/pelican/plugins/md_include $out
-        '';
-      });
-  in {
-    devShells = {
-      default = pkgs.mkShell {
-        nativeBuildInputs = with pkgs; [
-          lefthook
-          go-task
-          convco
-          typos
-          shellcheck
-          shfmt
-          python3
-          python3Packages.pelican
-          python3Packages.markdown-include
-          python3Packages.typogrify
-          python3Packages.livereload
-          python3Packages.invoke
-          rsync
-        ];
-        shellHook = ''
-          mkdir -p plugins
-          ln -snf "${pelicanplugins-neighbors}" "plugins/neighbors"
-          ln -snf "${pelicanplugins-md_include}" "plugins/md_include"
-        '';
-      };
+  outputs =
+    inputs@{
+      nixpkgs,
+      flake-parts,
+      systems,
+      ...
+    }:
+    flake-parts.lib.mkFlake { inherit inputs; } {
+      systems = [ "x86_64-linux" ];
+      imports = [
+        inputs.treefmt-nix.flakeModule
+        ./nix/default.nix
+      ];
     };
-  });
 }