feat: added flake

flake.nix

@@ -0,0 +1,88 @@
+{
+  inputs = {
+    nixpkgs.url = "github:NixOS/nixpkgs/nixos-unstable";
+    flake-utils.url = "github:numtide/flake-utils";
+    gitignore = {
+      url = "github:hercules-ci/gitignore.nix";
+      inputs.nixpkgs.follows = "nixpkgs";
+    };
+  };
+
+  outputs = { self, nixpkgs, flake-utils, gitignore, ... }:
+    flake-utils.lib.eachDefaultSystem (system:
+      let
+        pkgs = nixpkgs.legacyPackages.${system};
+        lib = pkgs.lib;
+
+        packageJSON = lib.importJSON ./package.json;
+        gitignoreSource = gitignore.lib.gitignoreSource;
+
+        pname = packageJSON.name;
+        version = packageJSON.version;
+
+        src = gitignoreSource ./.;
+      in
+      {
+        packages = rec {
+          hexname-frontend = pkgs.stdenv.mkDerivation {
+            inherit pname version src;
+
+            nativeBuildInputs = [
+              pkgs.deno
+              # pkgs.nodejs
+            ];
+
+            # Deno wants a writable cache
+            DENO_DIR = "$TMPDIR/deno";
+
+            # Ensure reproducibility
+            DENO_NO_UPDATE_CHECK = "1";
+            DENO_NO_PROMPT = "1";
+
+            buildPhase = ''
+              runHook preBuild
+
+              export HOME=$TMPDIR
+
+              # Cache all deps first (offline build safety)
+              deno cache --lock=deno.lock --frozen-lockfile \
+                ./vite.config.ts
+
+              # SvelteKit build
+              deno task build
+
+              runHook postBuild
+            '';
+
+            installPhase = ''
+              runHook preInstall
+
+              mkdir -p $out
+
+              cp -r build $out/
+              cp -r .svelte-kit $out/ || true
+              cp package.json $out/
+
+              runHook postInstall
+            '';
+
+            # No runtime deps
+            dontFixup = true;
+          };
+
+          default = hexname-frontend;
+        };
+
+        devShells.default = pkgs.mkShell {
+          buildInputs = [
+            pkgs.deno
+            # pkgs.nodejs
+          ];
+
+          DENO_DIR = ".deno";
+          DENO_NO_UPDATE_CHECK = "1";
+        };
+      }
+    );
+}
+