chore: use Nix for CI builds and add packages.default to flake

Replace actions/setup-go and golangci-lint-action with Nix installer
and cache actions, run all commands via nix develop. Add buildGoModule
package output and build-release job for multi-platform binary uploads.

Author: iamralch

.github/workflows/ci.yml

@@ -18,27 +18,22 @@ jobs:
       - name: Checkout
         uses: actions/checkout@v6
 
-      - name: Set up Go
-        uses: actions/setup-go@v6
-        with:
-          go-version-file: go.mod
-          cache: true
+      - name: Install Nix
+        uses: DeterminateSystems/nix-installer-action@v22
 
-      - name: Download dependencies
-        run: go mod download
+      - name: Setup Nix Cache
+        uses: DeterminateSystems/magic-nix-cache-action@v13
 
       - name: Run Tests
-        run: go tool ginkgo run -coverprofile=coverage.out -covermode=atomic ./...
+        run: nix develop --command go tool ginkgo run -coverprofile=coverage.out -covermode=atomic ./...
 
       - name: Run octocov
         uses: k1LoW/octocov-action@v1
         with:
           github-token: ${{ secrets.GITHUB_TOKEN }}
 
       - name: Run golangci-lint
-        uses: golangci/golangci-lint-action@v9
-        with:
-          version: latest
+        run: nix develop --command golangci-lint run
 
   release:
     needs: build
@@ -58,3 +53,37 @@ jobs:
           manifest-file: .github/config/release-please-manifest.json
           config-file: .github/config/release-please-config.json
           target-branch: main
+
+  build-release:
+    needs: release
+    if: ${{ needs.release.outputs.release_created }}
+    strategy:
+      matrix:
+        include:
+          - os: ubuntu-latest
+            nix_system: x86_64-linux
+          - os: macos-14
+            nix_system: aarch64-darwin
+    runs-on: ${{ matrix.os }}
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v6
+
+      - name: Install Nix
+        uses: DeterminateSystems/nix-installer-action@v22
+
+      - name: Setup Nix Cache
+        uses: DeterminateSystems/magic-nix-cache-action@v13
+
+      - name: Build with Nix
+        run: nix build . --system ${{ matrix.nix_system }}
+
+      - name: Prepare Release Assets
+        run: |
+          mkdir -p release && install -m 0755 result/bin/sqlc-gen-queries release/sqlc-gen-queries-${{ matrix.nix_system }}
+
+      - name: Upload Release Assets
+        uses: softprops/action-gh-release@v2
+        with:
+          tag_name: ${{ needs.release.outputs.tag_name }}
+          files: release/sqlc-gen-queries-${{ matrix.nix_system }}

flake.nix

@@ -1,5 +1,5 @@
 {
-  description = "sqlc-gen-queries development environment";
+  description = "sqlc-gen-queries - SQLC Queries Generator";
 
   inputs = {
     nixpkgs.url = "github:NixOS/nixpkgs/nixpkgs-unstable";
@@ -11,14 +11,29 @@
     flake-utils.lib.eachDefaultSystem (
       system:
       let
-        pkgs = import nixpkgs { inherit system; };
+        pkgs = nixpkgs.legacyPackages.${system};
+        version = (pkgs.lib.importJSON ./.github/config/release-please-manifest.json).".";
       in
       {
+        packages.default = pkgs.buildGoModule {
+          pname = "sqlc-gen-queries";
+          inherit version;
+          src = pkgs.lib.cleanSource ./.;
+          subPackages = [ "cmd/sqlc-gen-queries" ];
+          vendorHash = pkgs.lib.fakeHash; # replace with real hash after running `nix build`
+          meta = with pkgs.lib; {
+            description = "SQLC Queries Generator";
+            license = licenses.mit;
+            mainProgram = "sqlc-gen-queries";
+          };
+        };
+
         devShells.default = pkgs.mkShell {
           name = "sqlc-gen-queries";
-          packages = [
-            pkgs.go_1_25
-            pkgs.gopls
+          packages = with pkgs; [
+            go
+            golangci-lint
+            gopls
           ];
         };
       }