chore(nix): nix setup and dev shell

.envrc

@@ -0,0 +1 @@
+use flake

.gitignore

@@ -20,3 +20,4 @@ go.work.sum
 
 # env file
 .env
+.direnv

flake.lock

@@ -0,0 +1,27 @@
+{
+  "nodes": {
+    "nixpkgs": {
+      "locked": {
+        "lastModified": 1767640445,
+        "narHash": "sha256-UWYqmD7JFBEDBHWYcqE6s6c77pWdcU/i+bwD6XxMb8A=",
+        "owner": "nixos",
+        "repo": "nixpkgs",
+        "rev": "9f0c42f8bc7151b8e7e5840fb3bd454ad850d8c5",
+        "type": "github"
+      },
+      "original": {
+        "owner": "nixos",
+        "ref": "nixos-unstable",
+        "repo": "nixpkgs",
+        "type": "github"
+      }
+    },
+    "root": {
+      "inputs": {
+        "nixpkgs": "nixpkgs"
+      }
+    }
+  },
+  "root": "root",
+  "version": 7
+}

flake.nix

@@ -0,0 +1,58 @@
+{
+  inputs = {
+    nixpkgs.url = "github:nixos/nixpkgs/nixos-unstable";
+  };
+  outputs = {
+    self,
+    nixpkgs,
+    ...
+  }: let
+    systems = [
+      "x86_64-linux"
+      "aarch64-linux"
+      "x86_64-darwin"
+      "aarch64-darwin"
+    ];
+    forAllSystems = f:
+      nixpkgs.lib.genAttrs systems (system: let
+        pkgs = import nixpkgs {inherit system;};
+      in
+        f {
+          inherit (pkgs) lib stdenv;
+          inherit pkgs;
+        });
+  in {
+    devShells = forAllSystems ({pkgs, ...}: {
+      default = pkgs.mkShell {
+        CGO_ENABLED = "0";
+        hardeningDisable = ["all"];
+
+        buildInputs = with pkgs; [
+          # Go tools
+          go
+          golangci-lint
+          gofumpt
+          gotools
+          delve
+        ];
+      };
+    });
+    packages = forAllSystems ({
+      pkgs,
+      lib,
+      stdenv,
+      ...
+    }: {
+      default = self.packages.${stdenv.hostPlatform.system}.depgraph;
+      depgraph = pkgs.buildGo125Module {
+        pname = "depgraph";
+        version = "0.0.0";
+        src = lib.cleanSource ./.;
+        vendorHash = null;
+        meta = {
+          license = lib.licenses.mpl20;
+        };
+      };
+    });
+  };
+}