feat: add build-nix workflow

.forgejo/workflows/build-nix.yml

@@ -0,0 +1,71 @@
+name: Build / Static via Nix
+
+concurrency:
+  group: "build-nix-${{ forge.ref }}"
+  cancel-in-progress: true
+
+on:
+  push:
+    tags:
+      - "v*.*.*"
+  workflow_dispatch:
+  schedule:
+    - cron: '30 0 * * *'
+
+jobs:
+  build:
+    name: "Build Binaries"
+    runs-on: ubuntu-latest
+
+    strategy:
+      matrix:
+        include:
+          - package: default-static-x86_64
+            filename: conduwuit-linux-static-amd64
+          - package: default-static-aarch64
+            filename: conduwuit-linux-static-arm64
+
+          - package: max-perf-static-aarch64
+            filename: conduwuit-linux-static-arm64-maxperf
+          - package: max-perf-haswell-static-x86_64
+            filename: conduwuit-haswell-linux-static-amd64-maxperf
+
+    steps:
+      - uses: actions/checkout@df4cb1c069e1874edd31b4311f1884172cec0e10
+
+      - name: Install Lix
+        uses: https://github.com/samueldr/lix-gha-installer-action@a0fee77b2a98bb7c5c0ed7ae6d6ad4903dbdad0d
+        with:
+          extra_nix_config: experimental-features = nix-command flakes flake-self-attrs
+
+      - name: Build static binary
+        run: |
+          nix build .#${{ matrix.package }}
+          install -D result/bin/conduwuit /tmp/binaries/${{ matrix.filename }}
+
+      - name: Upload binary artifact
+        uses: forgejo/upload-artifact@v4
+        with:
+          name: ${{ matrix.filename }}
+          path: /tmp/binaries/${{ matrix.filename }}
+
+  release-binaries:
+    name: "Release Binaries"
+    runs-on: ubuntu-latest
+    needs:
+      - build
+    permissions:
+      contents: write
+    if: startsWith(github.ref, 'refs/tags/')
+    steps:
+      - name: Download binary artifacts
+        uses: forgejo/download-artifact@v4
+        with:
+          pattern: conduwuit*
+          path: binaries
+          merge-multiple: true
+      - name: Create Release and Upload
+        uses: https://github.com/softprops/action-gh-release@b4309332981a82ec1c5618f44dd2e27cc8bfbfda # v3
+        with:
+          draft: true
+          files: binaries/*