Add GitHub workflows

.github/workflows/build-docker.yml

@@ -0,0 +1,16 @@
+name: Build - Docker
+
+on:
+  push:
+    branches: ["master"]
+  pull_request:
+    branches: ["master"]
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+
+    steps:
+      - uses: actions/checkout@v3
+      - name: Build the Docker image
+        run: docker build . --file Dockerfile --tag git.supernets.org/supernets/hardlounge:$(date +%s)

.github/workflows/build.yml

@@ -0,0 +1,48 @@
+name: Build
+
+permissions:
+  contents: read
+
+on: [push, pull_request]
+
+jobs:
+  build:
+    name: Node ${{ matrix.node_version }} on ${{ matrix.os }}
+
+    strategy:
+      matrix:
+        include:
+          # EOL: April 2024
+          - os: ubuntu-latest
+            node_version: 16.x
+          - os: macOS-latest
+            node_version: 18.x
+          - os: windows-latest
+            node_version: 18.x
+          # EOL: April 2025
+          - os: ubuntu-latest
+            node_version: 18.x
+          # EOL: April 2026
+          - os: ubuntu-latest
+            node_version: 20.x
+
+    runs-on: ${{ matrix.os }}
+
+    steps:
+      - uses: actions/checkout@master
+
+      - name: Setup Node.js
+        uses: actions/setup-node@v4
+        with:
+          node-version: ${{ matrix.node_version }}
+
+      - name: Install
+        run: yarn --frozen-lockfile --non-interactive
+
+      - name: Build
+        run: yarn build
+        env:
+          NODE_ENV: production
+
+      - name: Test
+        run: yarn test