feat: add nix flake for dev shell

.envrc

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

.gitignore

@@ -2,6 +2,7 @@
 node_modules
 /dist*
 *.zip
+.direnv/
 
 # local env files
 .env.local

flake.lock

@@ -0,0 +1,25 @@
+{
+  "nodes": {
+    "nixpkgs": {
+      "locked": {
+        "lastModified": 1664753041,
+        "narHash": "sha256-0ogaD8PaGHluARFeupofvk1Nq9gpVeZdlFM0Kcwguys=",
+        "owner": "NixOS",
+        "repo": "nixpkgs",
+        "rev": "a62844b302507c7531ad68a86cb7aa54704c9cb4",
+        "type": "github"
+      },
+      "original": {
+        "id": "nixpkgs",
+        "type": "indirect"
+      }
+    },
+    "root": {
+      "inputs": {
+        "nixpkgs": "nixpkgs"
+      }
+    }
+  },
+  "root": "root",
+  "version": 7
+}

flake.nix

@@ -0,0 +1,10 @@
+{
+  description = "Vikunja frontend dev environment";
+
+  outputs = { self, nixpkgs }:
+    let pkgs = nixpkgs.legacyPackages.x86_64-linux;
+    in {
+      defaultPackage.x86_64-linux =
+        pkgs.mkShell { buildInputs = [ pkgs.nodePackages.pnpm pkgs.cypress ]; };
+    };
+}