feat: add NixOS configuration with direnv support

- Add flake.nix with dev shell
- Add NixOS module for Azion runtime config
- Add direnv .envrc for auto-activation
- Update .gitignore with .p*, result, .worktrees/, docs/, .direnv/

flake.nix

@@ -0,0 +1,71 @@
+{
+  description = "AZion Scheduler - React SPA for scheduling tasks";
+
+  inputs = {
+    nixpkgs.url = "github:nixos/nixpkgs/nixos-25.11";
+  };
+
+  outputs = {
+    self,
+    nixpkgs,
+  }: let
+    systems = [
+      "aarch64-linux"
+      "x86_64-linux"
+    ];
+
+    forAllSystems = nixpkgs.lib.genAttrs systems;
+  in {
+    nixosModules.default = import ./nixos;
+
+    devShells = forAllSystems (system: let
+      pkgs = nixpkgs.legacyPackages.${system};
+    in {
+      default = pkgs.mkShell {
+        name = "azion-scheduler-dev";
+
+        buildInputs = with pkgs; [
+          nodejs_22
+          nodePackages.typescript
+        ];
+
+        shellHook = ''
+          echo "AZion Scheduler Development Environment"
+          echo ""
+          echo "Available commands:"
+          echo "  npm run dev     - Start development server"
+          echo "  npm run build   - Build for production"
+          echo "  npm run preview - Preview production build"
+          echo ""
+          echo "Node version: $(node --version)"
+          echo "NPM version:  $(npm --version)"
+          echo "=========================================="
+        '';
+      };
+    });
+
+    packages = forAllSystems (system: let
+      pkgs = nixpkgs.legacyPackages.${system};
+    in {
+      default = pkgs.buildNpmPackage {
+        pname = "azion-scheduler";
+        version = "2.0.0";
+
+        src = self;
+
+        npmDepsHash = "sha256-/4YWme2q0MSQkhdAfDJwNP/qxCBtNC/FNTi41Uejdy0=";
+
+        installPhase = ''
+          runHook preInstall
+          cp -r dist $out
+          runHook postInstall
+        '';
+
+        meta = with pkgs.lib; {
+          description = "AZion Scheduler web UI";
+          platforms = platforms.linux;
+        };
+      };
+    });
+  };
+}