feat: add nix packaging (#480)

* feat: add Nix flake and module for hermes-workspace deployment

* chore: modernize Nix build by migrating to generic nodejs/pnpm packages and adding direnv integration

Author: MRDGH2821

.envrc

@@ -0,0 +1,3 @@
+#!/usr/bin/env bash
+
+use flake

.gitignore

@@ -1,3 +1,8 @@
+# Nix build outputs
+result
+result-*
+.direnv/
+
 # Dependencies
 node_modules
 .pnp

flake.lock

@@ -0,0 +1,119 @@
+{
+  description = "Hermes Workspace — desktop workspace for Hermes Agent";
+
+  inputs = {
+    nixpkgs.url = "github:NixOS/nixpkgs/nixos-unstable";
+    flake-utils.url = "github:numtide/flake-utils";
+  };
+
+  outputs =
+    {
+      self,
+      nixpkgs,
+      flake-utils,
+    }:
+    let
+      # -----------------------------------------------------------------------
+      # NixOS module — available on all systems
+      # -----------------------------------------------------------------------
+      nixosModules.default = import ./nix/module.nix;
+      nixosModules.hermes-workspace = nixosModules.default;
+
+      # Overlay that adds hermes-workspace into any nixpkgs instance
+      overlays.default = final: _prev: {
+        hermes-workspace = final.callPackage ./nix/package.nix { };
+      };
+      overlays.hermes-workspace = overlays.default;
+    in
+    # -----------------------------------------------------------------------
+    # Per-system outputs
+    # -----------------------------------------------------------------------
+    flake-utils.lib.eachDefaultSystem (
+      system:
+      let
+        pkgs = import nixpkgs {
+          inherit system;
+          overlays = [ overlays.default ];
+        };
+      in
+      {
+        # -----------------------------------------------------------------
+        # Packages
+        # -----------------------------------------------------------------
+        packages = {
+          default = pkgs.hermes-workspace;
+          hermes-workspace = pkgs.hermes-workspace;
+        };
+
+        # -----------------------------------------------------------------
+        # Apps  (nix run .  or  nix run .#hermes-workspace)
+        # -----------------------------------------------------------------
+        apps =
+          let
+            app = {
+              type = "app";
+              program = "${pkgs.hermes-workspace}/bin/hermes-workspace";
+            };
+          in
+          {
+            default = app;
+            hermes-workspace = app;
+          };
+
+        # -----------------------------------------------------------------
+        # Dev shell  (nix develop)
+        # -----------------------------------------------------------------
+        devShells.default = pkgs.mkShell {
+          name = "hermes-workspace-dev";
+
+          packages = with pkgs; [
+            # Node / JS toolchain
+            nodejs
+            pnpm
+            typescript
+
+            # Python for pty-helper and build scripts
+            python3
+
+            # Nix tooling
+            nil           # Nix LSP
+            nixfmt-rfc-style
+          ];
+
+          shellHook = ''
+            echo ""
+            echo "  🚀 hermes-workspace dev shell"
+            echo "     node  $(node --version)"
+            echo "     pnpm  $(pnpm --version)"
+            echo "     python $(python3 --version)"
+            echo ""
+            echo "  Quick start:"
+            echo "     pnpm install"
+            echo "     pnpm dev          # Vite dev server on :3000"
+            echo "     pnpm build        # Production build → dist/"
+            echo "     node server-entry.js  # Serve production build"
+            echo ""
+          '';
+        };
+
+        # -----------------------------------------------------------------
+        # Formatter  (nix fmt)
+        # -----------------------------------------------------------------
+        formatter = pkgs.nixfmt-rfc-style;
+
+        # -----------------------------------------------------------------
+        # Checks  (nix flake check)
+        # -----------------------------------------------------------------
+        checks = {
+          # Verify the package evaluates without building it
+          package-eval = pkgs.runCommand "hermes-workspace-pkg-eval" { } ''
+            echo "Package evaluated: ${pkgs.hermes-workspace.name}" > $out
+          '';
+        };
+      }
+    )
+    // {
+      # Expose module + overlay at the top level (system-agnostic)
+      inherit nixosModules overlays;
+    };
+}