ci: add automated quality checks

.github/workflows/server-ci.yml

@@ -0,0 +1,45 @@
+name: Server CI
+
+on:
+  push:
+    branches: [main]
+  pull_request:
+    branches: [main]
+  workflow_dispatch:
+
+permissions:
+  contents: read
+
+concurrency:
+  group: server-ci-${{ github.workflow }}-${{ github.ref }}
+  cancel-in-progress: true
+
+jobs:
+  validate:
+    name: Validate Python source and container
+    runs-on: ubuntu-latest
+    timeout-minutes: 20
+    steps:
+      - name: Check out source
+        uses: actions/checkout@v4
+
+      - name: Set up Python
+        uses: actions/setup-python@v5
+        with:
+          python-version: "3.12"
+          cache: pip
+          cache-dependency-path: requirements.txt
+
+      - name: Install dependencies
+        run: |
+          python -m pip install --upgrade pip
+          pip install -r requirements.txt
+
+      - name: Compile Python source
+        run: python -m compileall -q app
+
+      - name: Check installed dependencies
+        run: pip check
+
+      - name: Build Docker image
+        run: docker build --tag openkey-server:ci .