feat: add nix flake

.envrc

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

.gitignore

@@ -41,3 +41,5 @@ app-example
 # generated native folders
 /ios
 /android
+
+.direnv/

flake.lock

@@ -0,0 +1,27 @@
+{
+  "nodes": {
+    "nixpkgs": {
+      "locked": {
+        "lastModified": 1759977445,
+        "narHash": "sha256-LYr4IDfuihCkFAkSYz5//gT2r1ewcWBYgd5AxPzPLIo=",
+        "owner": "nixos",
+        "repo": "nixpkgs",
+        "rev": "2dad7af78a183b6c486702c18af8a9544f298377",
+        "type": "github"
+      },
+      "original": {
+        "owner": "nixos",
+        "ref": "nixpkgs-unstable",
+        "repo": "nixpkgs",
+        "type": "github"
+      }
+    },
+    "root": {
+      "inputs": {
+        "nixpkgs": "nixpkgs"
+      }
+    }
+  },
+  "root": "root",
+  "version": 7
+}

flake.nix

@@ -0,0 +1,20 @@
+{
+  inputs = {
+    nixpkgs.url = "github:nixos/nixpkgs/nixpkgs-unstable";
+  };
+  outputs = {nixpkgs, ...}: let
+    forAllSystems = function:
+      nixpkgs.lib.genAttrs nixpkgs.lib.systems.flakeExposed
+      (system: function nixpkgs.legacyPackages.${system});
+  in {
+    formatter = forAllSystems (pkgs: pkgs.alejandra);
+    devShells = forAllSystems (pkgs: {
+      default = pkgs.mkShell {
+        packages = with pkgs; [
+          corepack
+          nodejs_22
+        ];
+      };
+    });
+  };
+}