basic nix flake added

flake.nix

@@ -0,0 +1,36 @@
+{
+  description = "Komp AC - Kompress Accounting";
+
+  inputs = {
+    nixpkgs.url = "github:NixOS/nixpkgs/nixos-unstable";
+    flake-utils.url = "github:numtide/flake-utils";
+  };
+
+  outputs = { self, nixpkgs, flake-utils }:
+    flake-utils.lib.eachDefaultSystem (system:
+      let
+        pkgs = nixpkgs.legacyPackages.${system};
+      in
+      {
+        devShells.default = pkgs.mkShell {
+          buildInputs = with pkgs; [
+            # Rust toolchain
+            rustc
+            cargo
+            rustfmt
+            clippy
+            
+            # C build tools (for your linker issue)
+            gcc
+            binutils
+            pkg-config
+          ];
+
+          shellHook = ''
+            echo "🦀 Rust development environment loaded"
+            echo "Run 'cargo check' to verify everything works"
+          '';
+        };
+      }
+    );
+}