ci: add Nix flake verification workflow

.github/workflows/release.yml

@@ -50,6 +50,20 @@ jobs:
       - name: Set up Docker Buildx
         uses: docker/setup-buildx-action@v3
 
+      - name: Install Nix
+        if: hashFiles('flake.nix') != ''
+        uses: cachix/install-nix-action@v31
+        with:
+          github_access_token: ${{ secrets.GITHUB_TOKEN }}
+
+      - name: Flake schema check
+        if: hashFiles('flake.nix') != ''
+        run: nix flake check --no-build
+
+      - name: Nix build package
+        if: hashFiles('flake.nix') != ''
+        run: nix build
+
       - name: Run GoReleaser
         uses: goreleaser/goreleaser-action@v6
         with:

flake.nix

@@ -0,0 +1,47 @@
+{
+  description = "Lightweight, headless implementation of the KDE Connect protocol in Go";
+
+  inputs = {
+    nixpkgs.url = "github:NixOS/nixpkgs/nixos-unstable";
+    flake-utils.url = "github:numtide/flake-utils";
+  };
+
+  outputs = { self, nixpkgs, flake-utils }:
+    flake-utils.lib.eachDefaultSystem (system:
+      let
+        pkgs = nixpkgs.legacyPackages.${system};
+      in
+      {
+        packages.default = pkgs.buildGoModule {
+          pname = "kcd";
+          version = self.shortRev or "dirty";
+
+          src = ./.;
+
+          # Update when go.sum changes: nix build 2>&1 | grep 'got:' | awk '{print $2}'
+          vendorHash = "sha256-rnI60JzB8vtFC4iIVoHGi9um7f0mV7jbIJTNVu8ytVY=";
+
+          subPackages = [ "cmd/kcd" ];
+
+          env.CGO_ENABLED = "0";
+
+          ldflags = [
+            "-s" "-w"
+            "-X main.version=${self.shortRev or "dirty"}"
+          ];
+
+          meta = with pkgs.lib; {
+            description = "Headless KDE Connect daemon written in Go";
+            homepage = "https://github.com/bethropolis/kcd";
+            license = licenses.mit;
+            maintainers = [ ];
+            platforms = platforms.linux;
+          };
+        };
+
+        apps.default = flake-utils.lib.mkApp {
+          drv = self.packages.${system}.default;
+        };
+      }
+    );
+}